Preamble and header bit allocation for power savings within multiple user, multiple access, and/or MIMO wireless communications

ABSTRACT

Preamble and header bit allocation for power savings within multiple user, multiple access, and/or MIMO wireless communications. Within a multi-user packet, information (e.g., partial address information) related to a recipient group of wireless communication devices (e.g., as few as one wireless communication device or any subset of a number of wireless communication devices, sometimes including all of the wireless communication devices) is emplaced within a PHY (e.g., physical layer) header of such a multi-user packet to be communicated within a multi-user (MU) environment. Such recipient indicating information can be encoded with relatively higher robustness (e.g., lower coding rates, lower ordered modulation, cyclic redundancy check (CRC), etc.) that remaining portions of the multi-user packet. Various portions of the remainder of the multi-user packet may respectively correspond to different wireless communication devices (e.g., a first field for a first wireless communication device, a second field for a second wireless communication device, etc.).

CROSS REFERENCE TO RELATED PATENTS/PATENT APPLICATIONS ProvisionalPriority Claims

The present U.S. Utility Patent Application claims priority pursuant to35 U.S.C. §119(e) to the following U.S. Provisional Patent Applicationswhich are hereby incorporated herein by reference in their entirety andmade part of the present U.S. Utility Patent Application for allpurposes:

1. U.S. Provisional Application Ser. No. 61/303,162, entitled “WLAN nextgeneration header bit allocation and power saving options,” filed Feb.10, 2010, pending.

2. U.S. Provisional Patent Application Ser. No. 61/319,366, entitled“Efficient group ID for MU-MIMO transmissions in next generation WLAN,”filed Mar. 31, 2010, pending.

Incorporation by Reference

The following U.S. Utility Patent Applications are hereby incorporatedherein by reference in their entirety and are made part of the presentU.S. Utility Patent Application for all purposes:

1. U.S. Utility patent application Ser. No. 12/794,707, entitled“Cluster parsing for signaling within multiple user, multiple access,and/or MIMO wireless communications,” filed on Jun. 4, 2010, pending.

2. U.S. Utility patent application Ser. No. 12/794,711, entitled“Transmission acknowledgement within multiple user, multiple access,and/or MIMO wireless communications,” filed on Jun. 4, 2010, pending.

3. U.S. Utility patent application Ser. No. 12/796,654, entitled“Channel characterization and training within multiple user, multipleaccess, and/or MIMO wireless communications,” filed on Jun. 8, 2010,pending.

4. U.S. Utility patent application Ser. No. 12/796,655, entitled “Groupidentification and definition within multiple user, multiple access,and/or MIMO wireless communications,” filed on Jun. 8, 2010, pending.

5. U.S. Utility patent application Ser. No. 12/852,435, entitled“Management frame map directed operational parameters within multipleuser, multiple access, and/or MIMO wireless communications,” filed onAug. 6, 2010, pending.

6. U.S. Utility patent application Ser. No. 12/949,921, entitled “Groupidentification and definition employing look up table (LUT) withinmultiple user, multiple access, and/or MIMO wireless communications,”filed on Nov. 19, 2010, pending.

Incorporation by Reference

The following IEEE standards are hereby incorporated herein by referencein their entirety and are made part of the present U.S. Utility PatentApplication for all purposes:

1. IEEE Std 802.11™—2007, “IEEE Standard for Informationtechnology—Telecommunications and information exchange betweensystems—Local and metropolitan area networks—Specific requirements; Part11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)Specifications,” IEEE Computer Society, IEEE Std 802.11™—2007, (Revisionof IEEE Std 802.11-1999), 1233 pages.

2. IEEE Std 802.11n™—2009, “IEEE Standard for Informationtechnology—Telecommunications and information exchange betweensystems—Local and metropolitan area networks—Specific requirements; Part11: Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY)Specifications; Amendment 5: Enhancements for Higher Throughput,” IEEEComputer Society, IEEE Std 802.11n™—2009, (Amendment to IEEE Std802.11™—2007 as amended by IEEE Std 802.11k™—2008, IEEE Std802.11r™—2008, IEEE Std 802.11y™—2008, and IEEE Std 802.11r™—2009), 536pages.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The invention relates generally to communication systems; and, moreparticularly, it relates to preamble and header bit allocation for powersavings within multiple user, multiple access, and/or MIMO wirelesscommunications.

2. Description of Related Art

Communication systems are known to support wireless and wire linedcommunications between wireless and/or wire lined communication devices.Such communication systems range from national and/or internationalcellular telephone systems to the Internet to point-to-point in-homewireless networks. Each type of communication system is constructed, andhence operates, in accordance with one or more communication standards.For instance, wireless communication systems may operate in accordancewith one or more standards including, but not limited to, IEEE 802.11x,Bluetooth, advanced mobile phone services (AMPS), digital AMPS, globalsystem for mobile communications (GSM), code division multiple access(CDMA), local multi-point distribution systems (LMDS),multi-channel-multi-point distribution systems (MMDS), and/or variationsthereof.

Depending on the type of wireless communication system, a wirelesscommunication device, such as a cellular telephone, two-way radio,personal digital assistant (PDA), personal computer (PC), laptopcomputer, home entertainment equipment, et cetera communicates directlyor indirectly with other wireless communication devices. For directcommunications (also known as point-to-point communications), theparticipating wireless communication devices tune their receivers andtransmitters to the same channel or channels (e.g., one of the pluralityof radio frequency (RF) carriers of the wireless communication system)and communicate over that channel(s). For indirect wirelesscommunications, each wireless communication device communicates directlywith an associated base station (e.g., for cellular services) and/or anassociated access point (e.g., for an in-home or in-building wirelessnetwork) via an assigned channel. To complete a communication connectionbetween the wireless communication devices, the associated base stationsand/or associated access points communicate with each other directly,via a system controller, via the public switch telephone network, viathe Internet, and/or via some other wide area network.

For each wireless communication device to participate in wirelesscommunications, it includes a built-in radio transceiver (i.e., receiverand transmitter) or is coupled to an associated radio transceiver (e.g.,a station for in-home and/or in-building wireless communicationnetworks, RF modem, etc.). As is known, the receiver is coupled to theantenna and includes a low noise amplifier, one or more intermediatefrequency stages, a filtering stage, and a data recovery stage. The lownoise amplifier receives inbound RF signals via the antenna andamplifies then. The one or more intermediate frequency stages mix theamplified RF signals with one or more local oscillations to convert theamplified RF signal into baseband signals or intermediate frequency (IF)signals. The filtering stage filters the baseband signals or the IFsignals to attenuate unwanted out of band signals to produce filteredsignals. The data recovery stage recovers raw data from the filteredsignals in accordance with the particular wireless communicationstandard.

As is also known, the transmitter includes a data modulation stage, oneor more intermediate frequency stages, and a power amplifier. The datamodulation stage converts raw data into baseband signals in accordancewith a particular wireless communication standard. The one or moreintermediate frequency stages mix the baseband signals with one or morelocal oscillations to produce RF signals. The power amplifier amplifiesthe RF signals prior to transmission via an antenna.

Typically, the transmitter will include one antenna for transmitting theRF signals, which are received by a single antenna, or multiple antennae(alternatively, antennas), of a receiver. When the receiver includes twoor more antennae, the receiver will select one of them to receive theincoming RF signals. In this instance, the wireless communicationbetween the transmitter and receiver is a single-output-single-input(SISO) communication, even if the receiver includes multiple antennaethat are used as diversity antennae (i.e., selecting one of them toreceive the incoming RF signals). For SISO wireless communications, atransceiver includes one transmitter and one receiver. Currently, mostwireless local area networks (WLAN) that are IEEE 802.11, 802.11a,802,11b, or 802.11g employ SISO wireless communications.

Other types of wireless communications includesingle-input-multiple-output (SIMO), multiple-input-single-output(MISO), and multiple-input-multiple-output (MIMO). In a SIMO wirelesscommunication, a single transmitter processes data into radio frequencysignals that are transmitted to a receiver. The receiver includes two ormore antennae and two or more receiver paths. Each of the antennaereceives the RF signals and provides them to a corresponding receiverpath (e.g., LNA, down conversion module, filters, and ADCs). Each of thereceiver paths processes the received RF signals to produce digitalsignals, which are combined and then processed to recapture thetransmitted data.

For a multiple-input-single-output (MISO) wireless communication, thetransmitter includes two or more transmission paths (e.g., digital toanalog converter, filters, up-conversion module, and a power amplifier)that each converts a corresponding portion of baseband signals into RFsignals, which are transmitted via corresponding antennae to a receiver.The receiver includes a single receiver path that receives the multipleRF signals from the transmitter. In this instance, the receiver usesbeam forming to combine the multiple RF signals into one signal forprocessing.

For a multiple-input-multiple-output (MIMO) wireless communication, thetransmitter and receiver each include multiple paths. In such acommunication, the transmitter parallel processes data using a spatialand time encoding function to produce two or more streams of data. Thetransmitter includes multiple transmission paths to convert each streamof data into multiple RF signals. The receiver receives the multiple RFsignals via multiple receiver paths that recapture the streams of datautilizing a spatial and time decoding function. The recaptured streamsof data are combined and subsequently processed to recover the originaldata.

With the various types of wireless communications (e.g., SISO, MISO,SIMO, and MIMO), it would be desirable to use one or more types ofwireless communications to enhance data throughput within a WLAN. Forexample, high data rates can be achieved with MIMO communications incomparison to SISO communications. However, most WLAN include legacywireless communication devices (i.e., devices that are compliant with anolder version of a wireless communication standard). As such, atransmitter capable of MIMO wireless communications should also bebackward compatible with legacy devices to function in a majority ofexisting WLANs.

Therefore, a need exists for a WLAN device that is capable of high datathroughput and is backward compatible with legacy devices.

BRIEF SUMMARY OF THE INVENTION

The present invention is directed to apparatus and methods of operationthat are further described in the following Brief Description of theSeveral Views of the Drawings, the Detailed Description of theInvention, and the claims. Other features and advantages of the presentinvention will become apparent from the following detailed descriptionof the invention made with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a diagram illustrating an embodiment of a wirelesscommunication system.

FIG. 2 is a diagram illustrating an embodiment of a wirelesscommunication device.

FIG. 3 is a diagram illustrating an embodiment of a radio frequency (RF)transmitter.

FIG. 4 is a diagram illustrating an embodiment of an RF receiver.

FIG. 5 is a diagram illustrating an embodiment of a method for basebandprocessing of data.

FIG. 6 is a diagram illustrating an embodiment of a method that furtherdefines Step 120 of FIG. 5.

FIGS. 7-9 are diagrams illustrating various embodiments for encoding thescrambled data.

FIGS. 10A and 10B are diagrams illustrating embodiments of a radiotransmitter.

FIGS. 11A and 11B are diagrams illustrating embodiments of a radioreceiver.

FIG. 12 is a diagram illustrating an embodiment of an access point (AP)and multiple wireless local area network (WLAN) devices operatingaccording to one or more various aspects and/or embodiments of theinvention.

FIG. 13 is a diagram illustrating an embodiment of a wirelesscommunication device, and clusters, as may be employed for supportingcommunications with at least one additional wireless communicationdevice.

FIG. 14 is a diagram illustrating an embodiment of a preamble structureas may be employed within communications between wireless communicationdevices.

FIG. 15 is a diagram illustrating an embodiment of signal field bitallocation as may be employed within communications between wirelesscommunication devices.

FIG. 16 is a diagram illustrating an embodiment of power savingcomparison.

FIG. 17 is a diagram illustrating an embodiment comparing PHY headerduration and MAC receiver address (RA).

FIG. 18 is a diagram illustrating an embodiment of a packet in which aPHY portion (e.g., header) thereof includes information indicatingpacket recipients.

FIG. 19 is a diagram illustrating an embodiment of various groupidentification fields being transmitted to one or more receivingwireless communication devices.

FIG. 20 is a diagram illustrating an embodiment of communicationsbetween various wireless communication devices within a communicationsystem.

FIG. 21 is an alternative diagram illustrating an embodiment ofcommunications between various wireless communication devices within acommunication system.

FIG. 22, FIG. 23, FIG. 24A, and FIG. 24B illustrate embodiments ofmethods for operating wireless communication devices.

FIG. 25 is a diagram illustrating an embodiment of signal field bitallocation as may be employed within communications between wirelesscommunication devices in accordance with multi-user (MU) applications.

FIG. 26 is a diagram illustrating an embodiment of signal field bitallocation as may be employed within communications between wirelesscommunication devices in accordance with single-user (SU) applications.

FIG. 27 is a diagram illustrating an alternative embodiment of signalfield bit allocation as may be employed within communications betweenwireless communication devices.

FIG. 28 is a diagram illustrating yet another alternative embodiment ofsignal field bit allocation as may be employed within communicationsbetween wireless communication devices.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 is a diagram illustrating an embodiment of a wirelesscommunication system 10 that includes a plurality of base stationsand/or access points 12-16, a plurality of wireless communicationdevices 18-32 and a network hardware component 34. The wirelesscommunication devices 18-32 may be laptop host computers 18 and 26,personal digital assistant hosts 20 and 30, personal computer hosts 24and 32 and/or cellular telephone hosts 22 and 28. The details of anembodiment of such wireless communication devices is described ingreater detail with reference to FIG. 2.

The base stations (BSs) or access points (APs) 12-16 are operablycoupled to the network hardware 34 via local area network connections36, 38 and 40. The network hardware 34, which may be a router, switch,bridge, modem, system controller, et cetera provides a wide area networkconnection 42 for the communication system 10. Each of the base stationsor access points 12-16 has an associated antenna or antenna array tocommunicate with the wireless communication devices in its area.Typically, the wireless communication devices register with a particularbase station or access point 12-14 to receive services from thecommunication system 10. For direct connections (i.e., point-to-pointcommunications), wireless communication devices communicate directly viaan allocated channel.

Typically, base stations are used for cellular telephone systems (e.g.,advanced mobile phone services (AMPS), digital AMPS, global system formobile communications (GSM), code division multiple access (CDMA), localmulti-point distribution systems (LMDS), multi-channel-multi-pointdistribution systems (MMDS), Enhanced Data rates for GSM Evolution(EDGE), General Packet Radio Service (GPRS), high-speed downlink packetaccess (HSDPA), high-speed uplink packet access (HSUPA and/or variationsthereof) and like-type systems, while access points are used for in-homeor in-building wireless networks (e.g., IEEE 802.11, Bluetooth, ZigBee,any other type of radio frequency based network protocol and/orvariations thereof). Regardless of the particular type of communicationsystem, each wireless communication device includes a built-in radioand/or is coupled to a radio. Such wireless communication device mayoperate in accordance with the various aspects of the invention aspresented herein to enhance performance, reduce costs, reduce size,and/or enhance broadband applications.

FIG. 2 is a diagram illustrating an embodiment of a wirelesscommunication device that includes the host device 18-32 and anassociated radion 60. For cellular telephone hosts, the radion 60 is abuilt-in component. For personal digital assistants hosts, laptop hosts,and/or personal computer hosts, the radion 60 may be built-in or anexternally coupled component. For access points or base stations, thecomponents are typically housed in a single structure.

As illustrated, the host device 18-32 includes a processing module 50,memory 52, radio interface 54, input interface 58 and output interface56. The processing module 50 and memory 52 execute the correspondinginstructions that are typically done by the host device. For example,for a cellular telephone host device, the processing module 50 performsthe corresponding communication functions in accordance with aparticular cellular telephone standard.

The radio interface 54 allows data to be received from and sent to theradion 60. For data received from the radion 60 (e.g., inbound data),the radio interface 54 provides the data to the processing module 50 forfurther processing and/or routing to the output interface 56. The outputinterface 56 provides connectivity to an output display device such as adisplay, monitor, speakers, et cetera such that the received data may bedisplayed. The radio interface 54 also provides data from the processingmodule 50 to the radion 60. The processing module 50 may receive theoutbound data from an input device such as a keyboard, keypad,microphone, et cetera via the input interface 58 or generate the dataitself. For data received via the input interface 58, the processingmodule 50 may perform a corresponding host function on the data and/orroute it to the radion 60 via the radio interface 54.

Radio 60 includes a host interface 62, a baseband processing module 64,memory 66, a plurality of radio frequency (RF) transmitters 68-72, atransmit/receive (T/R) module 74, a plurality of antennae 82-86, aplurality of RF receivers 76-80, and a local oscillation module 100. Thebaseband processing module 64, in combination with operationalinstructions stored in memory 66, execute digital receiver functions anddigital transmitter functions, respectively. The digital receiverfunctions, as will be described in greater detail with reference to FIG.11B, include, but are not limited to, digital intermediate frequency tobaseband conversion, demodulation, constellation demapping, decoding,de-interleaving, fast Fourier transform, cyclic prefix removal, spaceand time decoding, and/or descrambling. The digital transmitterfunctions, as will be described in greater detail with reference tolater Figures, include, but are not limited to, scrambling, encoding,interleaving, constellation mapping, modulation, inverse fast Fouriertransform, cyclic prefix addition, space and time encoding, and/ordigital baseband to IF conversion. The baseband processing modules 64may be implemented using one or more processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on operationalinstructions. The memory 66 may be a single memory device or a pluralityof memory devices. Such a memory device may be a read-only memory,random access memory, volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, and/or any device that storesdigital information. Note that when the processing module 64 implementsone or more of its functions via a state machine, analog circuitry,digital circuitry, and/or logic circuitry, the memory storing thecorresponding operational instructions is embedded with the circuitrycomprising the state machine, analog circuitry, digital circuitry,and/or logic circuitry.

In operation, the radion 60 receives outbound data 88 from the hostdevice via the host interface 62. The baseband processing module 64receives the outbound data 88 and, based on a mode selection signal 102,produces one or more outbound symbol streams 90. The mode selectionsignal 102 will indicate a particular mode as are illustrated in themode selection tables, which appear at the end of the detaileddiscussion. For example, the mode selection signal 102, with referenceto table 1 may indicate a frequency band of 2.4 GHz or 5 GHz, a channelbandwidth of 20 or 22 MHz (e.g., channels of 20 or 22 MHz width) and amaximum bit rate of 54 megabits-per-second. In other embodiments, thechannel bandwidth may extend up to 1.28 GHz or wider with supportedmaximum bit rates extending to 1 gigabit-per-second or greater. In thisgeneral category, the mode selection signal will further indicate aparticular rate ranging from 1 megabit-per-second to 54megabits-per-second. In addition, the mode selection signal willindicate a particular type of modulation, which includes, but is notlimited to, Barker Code Modulation, BPSK, QPSK, CCK, 16 QAM and/or 64QAM. As is further illustrated in table 1, a code rate is supplied aswell as number of coded bits per subcarrier (NBPSC), coded bits per OFDMsymbol (NCBPS), data bits per OFDM symbol (NDBPS).

The mode selection signal may also indicate a particular channelizationfor the corresponding mode which for the information in table 1 isillustrated in table 2. As shown, table 2 includes a channel number andcorresponding center frequency. The mode select signal may furtherindicate a power spectral density mask value which for table 1 isillustrated in table 3. The mode select signal may alternativelyindicate rates within table 4 that has a 5 GHz frequency band, 20 MHzchannel bandwidth and a maximum bit rate of 54 megabits-per-second. Ifthis is the particular mode select, the channelization is illustrated intable 5. As a further alternative, the mode select signal 102 mayindicate a 2.4 GHz frequency band, 20 MHz channels and a maximum bitrate of 192 megabits-per-second as illustrated in table 6. In table 6, anumber of antennae may be utilized to achieve the higher bit rates. Inthis instance, the mode select would further indicate the number ofantennae to be utilized. Table 7 illustrates the channelization for theset-up of table 6. Table 8 illustrates yet another mode option where thefrequency band is 2.4 GHz, the channel bandwidth is 20 MHz and themaximum bit rate is 192 megabits-per-second. The corresponding table 8includes various bit rates ranging from 12 megabits-per-second to 216megabits-per-second utilizing 2-4 antennae and a spatial time encodingrate as indicated. Table 9 illustrates the channelization for table 8.The mode select signal 102 may further indicate a particular operatingmode as illustrated in table 10, which corresponds to a 5 GHz frequencyband having 40 MHz frequency band having 40 MHz channels and a maximumbit rate of 486 megabits-per-second. As shown in table 10, the bit ratemay range from 13.5 megabits-per-second to 486 megabits-per-secondutilizing 1-4 antennae and a corresponding spatial time code rate. Table10 further illustrates a particular modulation scheme code rate andNBPSC values. Table 11 provides the power spectral density mask fortable 10 and table 12 provides the channelization for table 10.

It is of course noted that other types of channels, having differentbandwidths, may be employed in other embodiments without departing fromthe scope and spirit of the invention. For example, various otherchannels such as those having 80 MHz, 120 MHz, and/or 160 MHz ofbandwidth may alternatively be employed such as in accordance with IEEETask Group ac (TGac VHTL6).

The baseband processing module 64, based on the mode selection signal102 produces the one or more outbound symbol streams 90, as will befurther described with reference to FIGS. 5-9 from the output data 88.For example, if the mode selection signal 102 indicates that a singletransmit antenna is being utilized for the particular mode that has beenselected, the baseband processing module 64 will produce a singleoutbound symbol stream 90. Alternatively, if the mode select signalindicates 2, 3 or 4 antennae, the baseband processing module 64 willproduce 2, 3 or 4 outbound symbol streams 90 corresponding to the numberof antennae from the output data 88.

Depending on the number of outbound streams 90 produced by the basebandmodule 64, a corresponding number of the RF transmitters 68-72 will beenabled to convert the outbound symbol streams 90 into outbound RFsignals 92. The implementation of the RF transmitters 68-72 will befurther described with reference to FIG. 3. The transmit/receive module74 receives the outbound RF signals 92 and provides each outbound RFsignal to a corresponding antenna 82-86.

When the radion 60 is in the receive mode, the transmit/receive module74 receives one or more inbound RF signals via the antennae 82-86. TheT/R module 74 provides the inbound RF signals 94 to one or more RFreceivers 76-80. The RF receiver 76-80, which will be described ingreater detail with reference to FIG. 4, converts the inbound RF signals94 into a corresponding number of inbound symbol streams 96. The numberof inbound symbol streams 96 will correspond to the particular mode inwhich the data was received (recall that the mode may be any one of themodes illustrated in tables 1-12). The baseband processing module 60receives the inbound symbol streams 90 and converts them into inbounddata 98, which is provided to the host device 18-32 via the hostinterface 62.

In one embodiment of radion 60 it includes a transmitter and a receiver.The transmitter may include a MAC module, a PLCP module, and a PMDmodule. The Medium Access Control (MAC) module, which may be implementedwith the processing module 64, is operably coupled to convert a MACService Data Unit (MSDU) into a MAC Protocol Data Unit (MPDU) inaccordance with a WLAN protocol. The Physical Layer ConvergenceProcedure (PLCP) Module, which may be implemented in the processingmodule 64, is operably coupled to convert the MPDU into a PLCP ProtocolData Unit (PPDU) in accordance with the WLAN protocol. The PhysicalMedium Dependent (PMD) module is operably coupled to convert the PPDUinto a plurality of radio frequency (RF) signals in accordance with oneof a plurality of operating modes of the WLAN protocol, wherein theplurality of operating modes includes multiple input and multiple outputcombinations.

An embodiment of the Physical Medium Dependent (PMD) module, which willbe described in greater detail with reference to FIGS. 10A and 10B,includes an error protection module, a demultiplexing module, and aplurality of direction conversion modules. The error protection module,which may be implemented in the processing module 64, is operablycoupled to restructure a PPDU (PLCP (Physical Layer ConvergenceProcedure) Protocol Data Unit) to reduce transmission errors producingerror protected data. The demultiplexing module is operably coupled todivide the error protected data into a plurality of error protected datastreams The plurality of direct conversion modules is operably coupledto convert the plurality of error protected data streams into aplurality of radio frequency (RF) signals.

As one of average skill in the art will appreciate, the wirelesscommunication device of FIG. 2 may be implemented using one or moreintegrated circuits. For example, the host device may be implemented onone integrated circuit, the baseband processing module 64 and memory 66may be implemented on a second integrated circuit, and the remainingcomponents of the radion 60, less the antennae 82-86, may be implementedon a third integrated circuit. As an alternate example, the radion 60may be implemented on a single integrated circuit. As yet anotherexample, the processing module 50 of the host device and the basebandprocessing module 64 may be a common processing device implemented on asingle integrated circuit. Further, the memory 52 and memory 66 may beimplemented on a single integrated circuit and/or on the same integratedcircuit as the common processing modules of processing module 50 and thebaseband processing module 64.

FIG. 3 is a diagram illustrating an embodiment of a radio frequency (RF)transmitter 68-72, or RF front-end, of the WLAN transmitter. The RFtransmitter 68-72 includes a digital filter and up-sampling module 75, adigital-to-analog conversion module 77, an analog filter 79, andup-conversion module 81, a power amplifier 83 and a RF filter 85. Thedigital filter and up-sampling module 75 receives one of the outboundsymbol streams 90 and digitally filters it and then up-samples the rateof the symbol streams to a desired rate to produce the filtered symbolstreams 87. The digital-to-analog conversion module 77 converts thefiltered symbols 87 into analog signals 89. The analog signals mayinclude an in-phase component and a quadrature component.

The analog filter 79 filters the analog signals 89 to produce filteredanalog signals 91. The up-conversion module 81, which may include a pairof mixers and a filter, mixes the filtered analog signals 91 with alocal oscillation 93, which is produced by local oscillation module 100,to produce high frequency signals 95. The frequency of the highfrequency signals 95 corresponds to the frequency of the RF signals 92.

The power amplifier 83 amplifies the high frequency signals 95 toproduce amplified high frequency signals 97. The RF filter 85, which maybe a high frequency band-pass filter, filters the amplified highfrequency signals 97 to produce the desired output RF signals 92.

As one of average skill in the art will appreciate, each of the radiofrequency transmitters 68-72 will include a similar architecture asillustrated in FIG. 3 and further include a shut-down mechanism suchthat when the particular radio frequency transmitter is not required, itis disabled in such a manner that it does not produce interferingsignals and/or noise.

FIG. 4 is a diagram illustrating an embodiment of an RF receiver. Thismay depict any one of the RF receivers 76-80. In this embodiment, eachof the RF receivers 76-80 includes an RF filter 101, a low noiseamplifier (LNA) 103, a programmable gain amplifier (PGA) 105, adown-conversion module 107, an analog filter 109, an analog-to-digitalconversion module 111 and a digital filter and down-sampling module 113.The RF filter 101, which may be a high frequency band-pass filter,receives the inbound RF signals 94 and filters them to produce filteredinbound RF signals. The low noise amplifier 103 amplifies the filteredinbound RF signals 94 based on a gain setting and provides the amplifiedsignals to the programmable gain amplifier 105. The programmable gainamplifier further amplifies the inbound RF signals 94 before providingthem to the down-conversion module 107.

The down-conversion module 107 includes a pair of mixers, a summationmodule, and a filter to mix the inbound RF signals with a localoscillation (LO) that is provided by the local oscillation module toproduce analog baseband signals. The analog filter 109 filters theanalog baseband signals and provides them to the analog-to-digitalconversion module 111 which converts them into a digital signal. Thedigital filter and down-sampling module 113 filters the digital signalsand then adjusts the sampling rate to produce the digital samples(corresponding to the inbound symbol streams 96).

FIG. 5 is a diagram illustrating an embodiment of a method for basebandprocessing of data. This diagram shows a method for converting outbounddata 88 into one or more outbound symbol streams 90 by the basebandprocessing module 64. The process begins at Step 110 where the basebandprocessing module receives the outbound data 88 and a mode selectionsignal 102. The mode selection signal may indicate any one of thevarious modes of operation as indicated in tables 1-12. The process thenproceeds to Step 112 where the baseband processing module scrambles thedata in accordance with a pseudo random sequence to produce scrambleddata. Note that the pseudo random sequence may be generated from afeedback shift register with the generator polynomial of S(x)=x⁷+x⁴+1.

The process then proceeds to Step 114 where the baseband processingmodule selects one of a plurality of encoding modes based on the modeselection signal. The process then proceeds to Step 116 where thebaseband processing module encodes the scrambled data in accordance witha selected encoding mode to produce encoded data. The encoding may bedone utilizing any one or more a variety of coding schemes (e.g.,convolutional coding, Reed-Solomon (RS) coding, turbo coding, turbotrellis coded modulation (TTCM) coding, LDPC (Low Density Parity Check)coding, etc.).

The process then proceeds to Step 118 where the baseband processingmodule determines a number of transmit streams based on the mode selectsignal. For example, the mode select signal will select a particularmode which indicates that 1, 2, 3, 4 or more antennae may be utilizedfor the transmission. Accordingly, the number of transmit streams willcorrespond to the number of antennae indicated by the mode selectsignal. The process then proceeds to Step 120 where the basebandprocessing module converts the encoded data into streams of symbols inaccordance with the number of transmit streams in the mode selectsignal. This step will be described in greater detail with reference toFIG. 6.

FIG. 6 is a diagram illustrating an embodiment of a method that furtherdefines Step 120 of FIG. 5. This diagram shows a method performed by thebaseband processing module to convert the encoded data into streams ofsymbols in accordance with the number of transmit streams and the modeselect signal. Such processing begins at Step 122 where the basebandprocessing module interleaves the encoded data over multiple symbols andsubcarriers of a channel to produce interleaved data. In general, theinterleaving process is designed to spread the encoded data overmultiple symbols and transmit streams. This allows improved detectionand error correction capability at the receiver. In one embodiment, theinterleaving process will follow the IEEE 802.11(a) or (g) standard forbackward compatible modes. For higher performance modes (e.g., IEEE802.11(n), the interleaving will also be done over multiple transmitpaths or streams.

The process then proceeds to Step 124 where the baseband processingmodule demultiplexes the interleaved data into a number of parallelstreams of interleaved data. The number of parallel streams correspondsto the number of transmit streams, which in turn corresponds to thenumber of antennae indicated by the particular mode being utilized. Theprocess then continues to Steps 126 and 128, where for each of theparallel streams of interleaved data, the baseband processing modulemaps the interleaved data into a quadrature amplitude modulated (QAM)symbol to produce frequency domain symbols at Step 126. At Step 128, thebaseband processing module converts the frequency domain symbols intotime domain symbols, which may be done utilizing an inverse fast Fouriertransform. The conversion of the frequency domain symbols into the timedomain symbols may further include adding a cyclic prefix to allowremoval of intersymbol interference at the receiver. Note that thelength of the inverse fast Fourier transform and cyclic prefix aredefined in the mode tables of tables 1-12. In general, a 64-pointinverse fast Fourier transform is employed for 20 MHz channels and128-point inverse fast Fourier transform is employed for 40 MHzchannels.

The process then proceeds to Step 130 where the baseband processingmodule space and time encodes the time domain symbols for each of theparallel streams of interleaved data to produce the streams of symbols.In one embodiment, the space and time encoding may be done by space andtime encoding the time domain symbols of the parallel streams ofinterleaved data into a corresponding number of streams of symbolsutilizing an encoding matrix. Alternatively, the space and time encodingmay be done by space and time encoding the time domain symbols ofM-parallel streams of interleaved data into P-streams of symbolsutilizing the encoding matrix, where P=2M In one embodiment the encodingmatrix may comprise a form of:

$\quad\begin{bmatrix}C_{1} & C_{2} & C_{3} & C_{4} & \ldots & C_{{2M} - 1} & C_{2M} \\{- C_{2}^{*}} & C_{1}^{*} & {- C_{4}^{*}} & C_{3}^{*} & \ldots & {- C_{2M}^{*}} & C_{{2M} - 1}\end{bmatrix}$The number of rows of the encoding matrix corresponds to M and thenumber of columns of the encoding matrix corresponds to P. Theparticular symbol values of the constants within the encoding matrix maybe real or imaginary numbers.

FIGS. 7-9 are diagrams illustrating various embodiments for encoding thescrambled data.

FIG. 7 is a diagram of one method that may be utilized by the basebandprocessing module to encode the scrambled data at Step 116 of FIG. 5. Inthis method, the encoding of FIG. 7 may include an optional Step 144where the baseband processing module may optionally perform encodingwith an outer Reed-Solomon (RS) code to produce RS encoded data. It isnoted that Step 144 may be conducted in parallel with Step 140 describedbelow.

Also, the process continues at Step 140 where the baseband processingmodule performs a convolutional encoding with a 64 state code andgenerator polynomials of G₀=133₈ and G₁=171₈ on the scrambled data (thatmay or may not have undergone RS encoding) to produce convolutionalencoded data. The process then proceeds to Step 142 where the basebandprocessing module punctures the convolutional encoded data at one of aplurality of rates in accordance with the mode selection signal toproduce the encoded data. Note that the puncture rates may include 1/2,2/3 and/or 3/4, or any rate as specified in tables 1-12. Note that, fora particular, mode, the rate may be selected for backward compatibilitywith IEEE 802.11(a), IEEE 802.11(g), or IEEE 802.11(n) raterequirements.

FIG. 8 is a diagram of another encoding method that may be utilized bythe baseband processing module to encode the scrambled data at Step 116of FIG. 5. In this embodiment, the encoding of FIG. 8 may include anoptional Step 148 where the baseband processing module may optionallyperform encoding with an outer RS code to produce RS encoded data. It isnoted that Step 148 may be conducted in parallel with Step 146 describedbelow.

The method then continues at Step 146 where the baseband processingmodule encodes the scrambled data (that may or may not have undergone RSencoding) in accordance with a complimentary code keying (CCK) code toproduce the encoded data. This may be done in accordance with IEEE802.11(b) specifications, IEEE 802.11(g), and/or IEEE 802.11(n)specifications.

FIG. 9 is a diagram of yet another method for encoding the scrambleddata at Step 116, which may be performed by the baseband processingmodule. In this embodiment, the encoding of FIG. 9 may include anoptional Step 154 where the baseband processing module may optionallyperform encoding with an outer RS code to produce RS encoded data.

Then, in some embodiments, the process continues at Step 150 where thebaseband processing module performs LDPC (Low Density Parity Check)coding on the scrambled data (that may or may not have undergone RSencoding) to produce LDPC coded bits. Alternatively, the Step 150 mayoperate by performing convolutional encoding with a 256 state code andgenerator polynomials of G₀=561₈ and G₁=753₈ on the scrambled data thescrambled data (that may or may not have undergone RS encoding) toproduce convolutional encoded data. The process then proceeds to Step152 where the baseband processing module punctures the convolutionalencoded data at one of the plurality of rates in accordance with a modeselection signal to produce encoded data. Note that the puncture rate isindicated in the tables 1-12 for the corresponding mode.

The encoding of FIG. 9 may further include the optional Step 154 wherethe baseband processing module combines the convolutional encoding withan outer Reed Solomon code to produce the convolutional encoded data.

FIGS. 10A and 10B are diagrams illustrating embodiments of a radiotransmitter. This may involve the PMD module of a WLAN transmitter. InFIG. 10A, the baseband processing is shown to include a scrambler 172,channel encoder 174, interleaver 176, demultiplexer 178, a plurality ofsymbol mappers 180-184, a plurality of inverse fast Fourier transform(IFFT)/cyclic prefix addition modules 186-190 and a space/time encoder192. The baseband portion of the transmitter may further include a modemanager module 175 that receives the mode selection signal 173 andproduces settings 179 for the radio transmitter portion and produces therate selection 171 for the baseband portion. In this embodiment, thescrambler 172, the channel encoder 174, and the interleave 176 comprisean error protection module. The symbol mappers 180-184, the plurality ofIFFT/cyclic prefix modules 186-190, the space time encoder 192 comprisea portion of the digital baseband processing module.

In operations, the scrambler 172 adds (e.g., in a Galois Finite Field(GF2)) a pseudo random sequence to the outbound data bits 88 to make thedata appear random. A pseudo random sequence may be generated from afeedback shift register with the generator polynomial of S(x)=x⁷+x⁴+1 toproduce scrambled data. The channel encoder 174 receives the scrambleddata and generates a new sequence of bits with redundancy. This willenable improved detection at the receiver. The channel encoder 174 mayoperate in one of a plurality of modes. For example, for backwardcompatibility with IEEE 802.11(a) and IEEE 802.11(g), the channelencoder has the form of a rate 1/2 convolutional encoder with 64 statesand a generator polynomials of G₀=133₈ and G₁=171₈. The output of theconvolutional encoder may be punctured to rates of 1/2, 2/3, and 3/4according to the specified rate tables (e.g., tables 1-12). For backwardcompatibility with IEEE 802.11(b) and the CCK modes of IEEE 802.11(g),the channel encoder has the form of a CCK code as defined in IEEE802.11(b). For higher data rates (such as those illustrated in tables 6,8 and 10), the channel encoder may use the same convolution encoding asdescribed above or it may use a more powerful code, including aconvolutional code with more states, any one or more of the varioustypes of error correction codes (ECCs) mentioned above (e.g., RS, LDPC,turbo, TTCM, etc.) a parallel concatenated (turbo) code and/or a lowdensity parity check (LDPC) block code. Further, any one of these codesmay be combined with an outer Reed Solomon code. Based on a balancing ofperformance, backward compatibility and low latency, one or more ofthese codes may be optimal. Note that the concatenated turbo encodingand low density parity check will be described in greater detail withreference to subsequent Figures.

The interleaver 176 receives the encoded data and spreads it overmultiple symbols and transmit streams. This allows improved detectionand error correction capabilities at the receiver. In one embodiment,the interleaver 176 will follow the IEEE 802.11(a) or (g) standard inthe backward compatible modes. For higher performance modes (e.g., suchas those illustrated in tables 6, 8 and 10), the interleaver willinterleave data over multiple transmit streams. The demultiplexer 178converts the serial interleave stream from interleaver 176 intoM-parallel streams for transmission.

Each symbol mapper 180-184 receives a corresponding one of theM-parallel paths of data from the demultiplexer. Each symbol mapper180-182 lock maps bit streams to quadrature amplitude modulated QAMsymbols (e.g., BPSK, QPSK, 16 QAM, 64 QAM, 256 QAM, et cetera) accordingto the rate tables (e.g., tables 1-12). For IEEE 802.11(a) backwardcompatibility, double Gray coding may be used.

The map symbols produced by each of the symbol mappers 180-184 areprovided to the IFFT/cyclic prefix addition modules 186-190, whichperforms frequency domain to time domain conversions and adds a prefix,which allows removal of inter-symbol interference at the receiver. Notethat the length of the IFFT and cyclic prefix are defined in the modetables of tables 1-12. In general, a 64-point IFFT will be used for 20MHz channels and 128-point IFFT will be used for 40 MHz channels.

The space/time encoder 192 receives the M-parallel paths of time domainsymbols and converts them into P-output symbols. In one embodiment, thenumber of M-input paths will equal the number of P-output paths. Inanother embodiment, the number of output paths P will equal 2M paths.For each of the paths, the space/time encoder multiples the inputsymbols with an encoding matrix that has the form of

$\begin{bmatrix}C_{1} & C_{2} & C_{3} & C_{4} & \ldots & C_{{2M} - 1} & C_{2M} \\{- C_{2}^{*}} & C_{1}^{*} & {- C_{4}^{*}} & C_{3}^{*} & \ldots & {- C_{2M}^{*}} & C_{{2M} - 1}\end{bmatrix}.$

The rows of the encoding matrix correspond to the number of input pathsand the columns correspond to the number of output paths.

FIG. 10B illustrates the radio portion of the transmitter that includesa plurality of digital filter/up-sampling modules 194-198,digital-to-analog conversion modules 200-204, analog filters 206-216,I/Q modulators 218-222, RF amplifiers 224-228, RF filters 230-234 andantennae 236-240. The P-outputs from the space/time encoder 192 arereceived by respective digital filtering/up-sampling modules 194-198. Inone embodiment, the digital filters/up sampling modules 194-198 are partof the digital baseband processing module and the remaining componentscomprise the plurality of RF front-ends. In such an embodiment, thedigital baseband processing module and the RF front end comprise adirect conversion module.

In operation, the number of radio paths that are active correspond tothe number of P-outputs. For example, if only one P-output path isgenerated, only one of the radio transmitter paths will be active. Asone of average skill in the art will appreciate, the number of outputpaths may range from one to any desired number.

The digital filtering/up-sampling modules 194-198 filter thecorresponding symbols and adjust the sampling rates to correspond withthe desired sampling rates of the digital-to-analog conversion modules200-204. The digital-to-analog conversion modules 200-204 convert thedigital filtered and up-sampled signals into corresponding in-phase andquadrature analog signals. The analog filters 208-214 filter thecorresponding in-phase and/or quadrature components of the analogsignals, and provide the filtered signals to the corresponding I/Qmodulators 218-222. The I/Q modulators 218-222 based on a localoscillation, which is produced by a local oscillator 100, up-convertsthe I/Q signals into radio frequency signals.

The RF amplifiers 224-228 amplify the RF signals which are thensubsequently filtered via RF filters 230-234 before being transmittedvia antennae 236-240.

FIGS. 11A and 11B are diagrams illustrating embodiments of a radioreceiver. These diagrams illustrate a schematic block diagram of anotherembodiment of a receiver. FIG. 11A illustrates the analog portion of thereceiver which includes a plurality of receiver paths. Each receiverpath includes an antenna, RF filters 252-256, low noise amplifiers258-260, I/Q demodulators 264-268, analog filters 270-280,analog-to-digital converters 282-286 and digital filters anddown-sampling modules 288-290.

In operation, the antennae receive inbound RF signals, which areband-pass filtered via the RF filters 252-256. The corresponding lownoise amplifiers 258-260 amplify the filtered signals and provide themto the corresponding I/Q demodulators 264-268. The I/Q demodulators264-268, based on a local oscillation, which is produced by localoscillator 100, down-converts the RF signals into baseband in-phase andquadrature analog signals.

The corresponding analog filters 270-280 filter the in-phase andquadrature analog components, respectively. The analog-to-digitalconverters 282-286 convert the in-phase and quadrature analog signalsinto a digital signal. The digital filtering and down-sampling modules288-290 filter the digital signals and adjust the sampling rate tocorrespond to the rate of the baseband processing, which will bedescribed in FIG. 11B.

FIG. 11B illustrates the baseband processing of a receiver. The basebandprocessing includes a space/time decoder 294, a plurality of fastFourier transform (FFT)/cyclic prefix removal modules 296-300, aplurality of symbol demapping modules 302-306, a multiplexer 308, adeinterleaver 310, a channel decoder 312, and a descramble module 314.The baseband processing module may further include a mode managingmodule 175, which produces rate selections 171 and settings 179 based onmode selections 173. The space/time decoding module 294, which performsthe inverse function of space/time encoder 192, receives P-inputs fromthe receiver paths and produce M-output paths. The M-output paths areprocessed via the FFT/cyclic prefix removal modules 296-300 whichperform the inverse function of the IFFT/cyclic prefix addition modules186-190 to produce frequency domain symbols.

The symbol demapping modules 302-306 convert the frequency domainsymbols into data utilizing an inverse process of the symbol mappers180-184. The multiplexer 308 combines the demapped symbol streams into asingle path.

The deinterleaver 310 deinterleaves the single path utilizing an inversefunction of the function performed by interleaver 176. The deinterleaveddata is then provided to the channel decoder 312 which performs theinverse function of channel encoder 174. The descrambler 314 receivesthe decoded data and performs the inverse function of scrambler 172 toproduce the inbound data 98.

FIG. 12 is a diagram illustrating an embodiment of an access point (AP)and multiple wireless local area network (WLAN) devices operatingaccording to one or more various aspects and/or embodiments of theinvention. The AP point 1200 may compatible with any number ofcommunication protocols and/or standards, e.g., IEEE 802.11(a), IEEE802.11(b), IEEE 802.11(g), IEEE 802.11(n), as well as in accordance withvarious aspects of invention. According to certain aspects of thepresent invention, the AP supports backwards compatibility with priorversions of the IEEE 802.11x standards as well. According to otheraspects of the present invention, the AP 1200 supports communicationswith the WLAN devices 1202, 1204, and 1206 with channel bandwidths, MIMOdimensions, and at data throughput rates unsupported by the prior IEEE802.11x operating standards. For example, the access point 1200 and WLANdevices 1202, 1204, and 1206 may support channel bandwidths from thoseof prior version devices and from 40 MHz to 1.28 GHz and above. Theaccess point 1200 and WLAN devices 1202, 1204, and 1206 support MIMOdimensions to 4×4 and greater. With these characteristics, the accesspoint 1200 and WLAN devices 1202, 1204, and 1206 may support datathroughput rates to 1 GHz and above.

The AP 1200 supports simultaneous communications with more than one ofthe WLAN devices 1202, 1204, and 1206. Simultaneous communications maybe serviced via OFDM tone allocations (e.g., certain number of OFDMtones in a given cluster), MIMO dimension multiplexing, or via othertechniques. With some simultaneous communications, the AP 1200 mayallocate one or more of the multiple antennae thereof respectively tosupport communication with each WLAN device 1202, 1204, and 1206, forexample.

Further, the AP 1200 and WLAN devices 1202, 1204, and 1206 are backwardscompatible with the IEEE 802.11 (a), (b), (g), and (n) operatingstandards. In supporting such backwards compatibility, these devicessupport signal formats and structures that are consistent with theseprior operating standards.

FIG. 13 is a diagram illustrating an embodiment of a wirelesscommunication device, and clusters, as may be employed for supportingcommunications with at least one additional wireless communicationdevice. Generally speaking, a cluster may be viewed as a depiction ofthe mapping of tones, such as for an OFDM symbol, within or among one ormore channels (e.g., sub-divided portions of the spectrum) that may besituated in one or more bands (e.g., portions of the spectrum separatedby relatively larger amounts). As an example, various channels of 20 MHzmay be situated within or centered around a 5 GHz band. The channelswithin any such band may be continuous (e.g., adjacent to one another)or discontinuous (e.g., separated by some guard interval or band gap).Oftentimes, one or more channels may be situated within a given band,and different bands need not necessarily have a same number of channelstherein. Again, a cluster may generally be understood as any combinationone or more channels among one or more bands. As may be seen in thediagram, any respective cluster may be associated with any one or moreantennae (including as few as one antenna as well as up to all of theantennae) of the wireless communication device.

The wireless communication device of this diagram may be of any of thevarious types and/or equivalents described herein (e.g., AP, WLANdevice, or other wireless communication device including, though notlimited to, any of those depicted in FIG. 1, etc.). The wirelesscommunication device includes multiple antennae from which one or moresignals may be transmitted to one or more receiving wirelesscommunication devices and/or received from one or more other wirelesscommunication devices.

Such clusters may be used for transmissions of signals via various oneor more selected antennae. For example, different clusters are shown asbeing used to transmit signals respectively using different one or moreantennae.

Within the various diagrams and embodiments described and depictedherein, wireless communication devices may generally be referred to asWDEVs. It is noted that such wireless communication devices may bewireless stations (STAs), access points (APs), or any other type ofwireless communication device without departing from the scope andspirit of the invention. Generally speaking, wireless communicationdevices that are APs may be referred to as transmitting wirelesscommunication devices, and wireless communication devices that are STAsmay be referred to as receiving wireless communication devices incertain contexts.

Of course, it is noted that the general nomenclature employed hereinwherein a transmitting wireless communication device (e.g., such asbeing an AP, or a STA operating as an ‘AP’ with respect to other STAs)initiates communications, and/or operates as a network controller typeof wireless communication device, with respect to a number of other,receiving wireless communication devices (e.g., such as being STAs), andthe receiving wireless communication devices (e.g., such as being STAs)responding to and cooperating with the transmitting wirelesscommunication device in supporting such communications. Of course, whilethis general nomenclature of transmitting wireless communicationdevice(s) and receiving wireless communication device(s) may be employedto differentiate the operations as performed by such different wirelesscommunication devices within a communication system, all such wirelesscommunication devices within such a communication system may of coursesupport bi-directional communications to and from other wirelesscommunication devices within the communication system. In other words,the various types of transmitting wireless communication device(s) andreceiving wireless communication device(s) may all supportbi-directional communications to and from other wireless communicationdevices within the communication system.

FIG. 14 is a diagram illustrating an embodiment of a preamble structureas may be employed within communications between wireless communicationdevices. With respect such references herein, devices that are compliantwith an older version of a wireless communication standard (e.g., alegacy) may be those compliant with earlier versions of IEEE 802.11x(where x may be a, b, g, n, etc.). Certain of the embodiments describedherein may not only be compliant with such legacy communicationprotocols, standards, and/or recommended practices, but may also becompliant with newer communication protocols, standards, and/orrecommended practices such as IEEE 802.11 ac, among others.

Packet construction in accordance with the various principles presentedherein, generally speaking, may include a preamble, a signal field, anda payload. Such a packet may also be viewed as being partitioned into aPHY portion (e.g., such as corresponding to a header of the packet) anda MAC portion, as will also be seen with respect to other embodiments.Generally, the preamble is used for carrier acquisition,synchronization, channel estimation, etc. The signal field is used tocommunicate frame specific parameters (e.g., coding rate, frame length,etc.) to a receiving device. The payload is the data portion of thepacket.

A frame format may be modified based on a number of parameters,including, dependence upon the presence of other wireless communicationdevices in a communication system. In some instances, a communicationmay include various types of wireless communication devices havingdifferent respective capability sets (e.g., legacy devices, newerdevices, mixed mode devices, etc.).

For example, with some embodiments, in the 5 GHz spectrum, legacydevices may include those being compliant in accordance with IEEE802.11a and IEEE 802.11n, among others. Legacy devices must be able torecognize a packet has been transmitted and remain off the air for theduration of the packet (i.e., remain off of the communication channel orcommunication medium giving access to other communication devices).Thus, packets formed in accordance with the various aspects presentedherein may include certain portions therein that are compliant withlegacy or prior standards, recommended practices, etc. As one example, anew packet may include a legacy preamble and a signal field along with anew, modified version of a payload. With such a novel packet structure,a legacy device will still be able to recognize the legacy preamble anddecode the legacy signal field. The legacy signal field containsinformation that tells the legacy devices how long the packet will be onthe air (i.e., occupy or be using the communication channel orcommunication medium). The legacy signal field does not contain IEEE802.11ac specific parameters (that is done in the IEEE 802.11ac signalfield).

Referring to FIG. 14, the preamble includes a legacy short trainingfield (L-STF), a legacy long training field (L-LTF), a legacy signalfield (L-SIG), at least one (e.g., a first) very high throughput signalfield (VHT-SIGA), a very high throughput short training field (VHT-STF),at least one very high throughput long training field (VHT-LTF), asecond very high throughput signal field (VHT-SIGB), followed by a datafield (VHT DATA).

In one embodiment, the VHT-SIGA field includes 48 bits, and the VHT-SIGBfield includes 24 bits. The length of the packet is determined by T, thelength extending from the end of the L-SIG field to the end of thepacket. In some instances, not all packets are the same length, asdiffering amounts of data may be included within different packets. TheL-SIG field may include a symbol mapped in accordance with theconstellation shown on the lower left portion of the diagram. TheVHT-SIGA field may be composed of two distinct symbols, symbol mapped inaccordance with the constellations shown at the bottom and the lowerright portions of the diagram. VHT auto-detection (e.g., to determine ifthe packet corresponds to non-legacy format) may be performed using theconstellation shown at the lower right portion of the diagram.

In accordance with such a preamble constructed in accordance with theseprinciples, early packet drop may be performed when the VHT-SIGA fieldincludes some information regarding those wireless communication devicesto which the packet is intended. For example, rather than a receivingwireless communication device needing to process virtually the entirepacket before extracting receiver address (RA) information from the MACportion of the packet, some information (e.g., partial addressinformation, etc.) may be included in the PHY header (e.g., the VHT-SIGAfield) to indicate to which receiving wireless communication devices thepacket is intended so that those wireless communication devices notincluded in the recipient group may modify the manner of processing thepacket. The modification of the processing of the packet, as performedby a receiving wireless communication device, may relate to dropping thepacket, ceasing to process the remainder of the packet, powering down,entering into stand-by or sleep mode, etc. Any of a variety of modifiedprocessing of the packet may be performed based on an earlydetermination of which receiving wireless communication devices thepacket is intended.

By performing such modified processing of the packet, power savings maybe effectuated within a receiving wireless communication device (e.g.,STA) that receives such a packet when that packet is not particularlyintended for that receiving wireless communication device (e.g., STA).For example, when a multi-user packet is transmitted from a transmittingwireless communication device to a number of receiving wirelesscommunication devices, yet the multi-user packet is actually onlyintended for a subset of those receiving wireless communication devices(e.g., as few as one, two or more yet less than all, etc.), then thosereceiving wireless communication devices that received the multi-userpacket may process a PHY header of the multi-user packet to determinevery quickly during the processing of the multi-user packet whether themulti-user packet is intended for that receiving wireless communicationdevice or not. If it is not, then the multi-user packet may be dropped,processing of the multi-user packet may cease, the receiving wirelesscommunication device may power down some (less than all) or its entirefunctionality/circuitry/etc. or enter a sleep mode or other powersavings operational mode, etc.

In some embodiments, preliminary information related to the recipientlist may be extracted from partial address information included withinthe PHY header. In certain embodiments, a group identification (groupID) related information located within the PHY header may be used toprovide such information. In addition, such information within the PHYheader may not only include information indicating for which receivingwireless communication devices the packet is intended, but suchinformation (and/or other information) within the PHY header may alsoindicate which portions of the multi-user packet are intended forrespective receiving wireless communication devices. For example, suchinformation within the PHY header can indicate for which receivingwireless communication devices the multi-user packet is intended, andthat same information within the PHY header (and/or other information inthe PHY header) may indicate respective fields within the multi-userpacket that are intended for different receiving wireless communicationdevices. Examples of some types of multi-user packets include those inaccordance with orthogonal frequency division multiple access (OFDMA),multi-user multiple input multiple output (MU-MIMO), combinationsthereof, etc.

FIG. 15 is a diagram illustrating an embodiment of signal field bitallocation as may be employed within communications between wirelesscommunication devices. This embodiment shows how group ID relatedinformation within a multi-user packet may be used to indicate suchinformation as described herein (e.g., PHY header information indicatingrecipients, respective fields intended for such recipients, etc.). Inanother embodiment, group ID may consist of 6 bits and the Nsts fieldmay consists of 12 bits, depending on how many bits are available in theVHT-SIGA field.

With the structure of this diagram, a non-sounding bit is included inthe VHT-SIG A field. When the non-sounding bit is set to 1, the packetis a single user or multi-user (SU/MU)-MIMO DATA packet. Each recipientSTA determines its STA number by examining the group ID in the SIGAfield and comparing it to a previously assigned set of group ID values,each of which ahs associated information including at least a set ofreceiving wireless communication devices (e.g., STAs) that are membersof that group ID and receiver (e.g., STA) number for the members of thatgroup ID. If a match of the group ID is found among the previouslyassigned group ID values, and the matching group ID includes thisreceiver (e.g., STA) as a group member, then the receiving wirelesscommunication device (e.g., STA) determines its receiver (STA) numberfrom the associated information. If a pre-assigned group ID (NOTE: groupID, GroupID, Group ID, and/or their respective equivalents, may be usedinterchangeably herein) is not used within the SIGA field, then theGroupID=0 or any specific or predetermined value to represent the packetis either SU-MIMO or Broadcast, which implies all STAs in a basicservices set (BSS) needs to decode the packet, and only the first 3 bitsof the Nsts field indicates the number of VHT-LTFs present in thestructure.

When the non-sounding bit is set to 0 the packet is a sounding packet.For such operation, typically the GroupID=0 (or a specific orpredetermined value) and the first 3 bits in the Nsts field indicatesthe number of VHT-LTFs to be sounded (other bits: b3-b8 can be used forsome other feature). If the GroupID of a sounding packet is non-zero(when the AP wants to reuse pre-assigned GroupID to sound STAs), all 9bits in FIG. 15 in the Nsts field are used. As mentioned elsewhereherein, it is noted that the Nsts field may be composed of a differentnumber of bits without departing from the scope and spirit of theinvention (e.g., the Nsts field may be 12 bits in another embodiment).However, only Nsts_k for STA_k, where k=1, 2, 3, 4 (e.g., Nsts_k beingthose space-time streams corresponding particularly to that STA) to besounded are not zero and the number of VHT-LTFs=sum(Nsts_k).

From certain perspectives, the use of group ID and group definitionfields in accordance with the various aspects presented herein may beviewed as moving media access control (MAC) addressing information tothe physical layer (PHY). This way, the receiving wireless communicationdevice is operative to determine (e.g., at the PHY level) if it is anintended receiving wireless communication device and also how it is toprocess a received transmission. By moving addressing information fromthe MAC to the PHY, such recipient related information may be determinedmuch sooner and earlier during the processing of the multi-user packetby various receiving wireless communication devices within acommunication system that is operative to accommodate MU operation.

In accordance with the description herein, the group ID fieldinformation may be used to enhance the effectiveness of power savingoperations, such as might be performed by receiving wirelesscommunication devices that may receive a multi-user packet including thestructure described herein. Such power savings may relate to dropping ofthe packet, ceasing processing completing PHY header processing,performing power down [all, partial, sleep mode, etc.], etc.

In accordance with the power saving that may be effectuated with anon-zero group ID, it may be seen that when resolvable LTFs are employedin combination with a group ID for MU-MIMO, each respective receivingwireless communication device (e.g., STA) can identify whether it is acandidate to be a recipient of the packet in a much earlier manner, forexample, when it detects VHT-SIGA as compared to waiting untilprocessing of the MAC portion of the packet to identify MAC addressinformation such as receiver address (RA), etc. to identify therecipient list. For example, if a receiving wireless communicationdevice (e.g., STA) identifies it is not in the list of recipients (e.g.,not a member of the group ID) by examining the group ID in VHT-SIGA andthe previously assigned group ID values, then that receiving wirelesscommunication device (e.g., STA) may drop the packet without efforts toprocess VHT-STFs, VHT-LTFs, VHT-SIGB, and a part of payload. In thisway, processing time up to at least 50% may be saved using suchpreliminary information within a PHY header of a packet (e.g., a packetwith group ID) compared to operating in accordance with processing theMAC portion of the packet to identify MAC address, RA information, etc.to identify whether the receiving wireless communication device (e.g.,STA) is included in the intended recipient list.

For example, considering some information related to a group IDembodiment, such as the following fields, with indicated respectivedurations, L-STF (8 μsec), L-LTF (8 μsec), L-SIG (8 μsec), VHT-SIGA (8μsec), VHT-STF (4 μsec), VHT-LTF (16 μsec for Nss=4), VHT-SIGB (4 μsec),first OFDM symbol in payload (4 μsec), a receiving wirelesscommunication device (e.g., STA) would not have to detect the fieldportions following VHT-SIGA if that receiving wireless communicationdevice (e.g., STA) drops the packet right after VHT-SIGA (e.g., afteremploying such information in the PHY header, which may be group ID insome embodiments to identify the recipient list and seeing that thatreceiving wireless communication device (e.g., STA) is not in therecipient list).

For SU-MIMO applications, such implementations can also save power whensuch information in the PHY header, which may be group ID, is used toperform such early detection of recipients as compared to using MACrelated information (e.g., early detection with Nsts=[0 8 0 0], whichmeans only the 2^(nd) STA has a non-zero number of streams [8 in thisexample], and the other STAs do not have any designated streams).

Considering the power savings as may be achieved in which group ID=0, ora specific or predetermined value, within SU-MIMO applications, if amanagement packet exchange is not employed in accordance with a SU-MIMOapplication (e.g., when operating in an open loop mode such as withoutpreliminarily providing a sounding frame), then there may not be a groupID assignment at that time [such as when a group definition field hasnot been received].

In such instances, group ID may be set to be zero (e.g., group ID=0), ora specific or predetermined value, with only first 3 bits valid in Nstsfield. The other 6 bits in the Nsts field (or 9 bits, in an alternativeembodiment) are still available for other usage. For example, these 6bits (or 9 bits, in an alternative embodiment) may be used for powersaving for SU-MIMO with group ID=0, or a specific or predetermined valueto represent it as a SU-MIMO packet.

As may be seen in FIG. 15, when group ID=0, or a specific orpredetermined value, for SU-MIMO, then the bits in the Nsts Field (TableIndex), b3 to b8 (6 bits) are available. These 6 bits may be used inother formats to indicate a portion of an association identifier (AID),for example, each bit in Nsts field associated with two bits of an AIDby XOR. In other words, 3 bits XOR may be performed (e.g., 1 bit in Nstsand 2 bits in AID) except for the last bit in AID (e.g., 1 bit in Nstsand 1 last bit in AID XOR).

The first 5 bits in the Nsts field may be used for the 5 LSB bits in AIDof the receiving wireless communication device (e.g., STA). In someembodiments, a transmitting wireless communication device (e.g., AP) maynotify a particular bit position for those 5 LSB bits in the AID, ifnecessary. In other words, the particular location of those bitpositions may be different within different communications (e.g., suchas bits b3 to b7 in the 11 bits of the AID), as defined by thetransmitting wireless communication device (e.g., AP). The AID may beassigned during the association process by a transmitting wirelesscommunication device (e.g., AP), and can be 11 bits in total. The last 1bit in the Nsts field may indicate whether the other 6 MSB bits in theAID have any non-zero value. In other embodiments, all of the 6 bits (or9 bits, in an alternative embodiment) can represent any part of AID(e.g., 11 bits in total). For example, 6 bits MSB or 6 bits LSB, or anypart of AID bits.

As may be understood when using information in accordance with a PHYheader to indicate a recipient list, some frames should not be droppedin accordance with PHY processing. For example, frames with long networkallocation vector (NAV) reservations, request to send (RTS), clear tosend (CTS), etc. should not be dropped even though a receiving wirelesscommunication device (e.g., STA) is not the intended recipient asdetermined by examining the RA field of these frames. Particular valuesand information may be employed in these frames to indicate that noreceiving wireless communication device (e.g., STA) can enter power saveduring such receptions to ensure receipt of MAC DUR information.

For example, for indicating that no receiving wireless communicationdevice (e.g., STA) should drop the frame (e.g., RTS/CTS), the bits b3 tob8 bits may all be set to zeros. An AID=0, or specific or particularvalue, may be used to indicate that there is no receiving wirelesscommunication device (e.g., STA) targeted as the recipient that mightenter power save, and therefore, all receiving wireless communicationdevices (e.g., STAs) may drop the reception. This situation would arisewhen the targeted recipient is a transmitting wireless communicationdevice (e.g., AP) which will never enter a power save mode.

FIG. 16 is a diagram illustrating an embodiment of power savingcomparison. Such a comparison for power savings calculation is made withrespect to an embodiment that employs PHY header related information todetermine a recipient list compared to an embodiment that employs MACrelated information. As may be seen, a significant amount of powersavings may be effectuated by performing recipient list determinationusing PHY header related information. For example, power savings ofapproximately 20% to 48% by early detection (e.g., using PHY headerinformation) of the recipient list to allow for modified processing(e.g., dropping of the packet, powering down, entering sleep mode, etc.)is achievable.

FIG. 17 is a diagram illustrating an embodiment comparing PHY headerduration and MAC receiver address (RA). Such an embodiment employs anexample with 4 space-time streams (STSs), though differing numbers ofSTSs may be employed without departing from the scope and spirit of theinvention. When appropriate information in a PHY header such as anon-zero group ID is used (e.g., group ID≠0), or a group ID≠a specificor predetermined group ID value, where such a specific or predeterminedgroup ID value is defined for SU-MIMO, is used with a management frameexchange, power savings may be achieved by identifying the list ofrecipients in VHT-SIGA.

When appropriate information in a PHY header such as a zero group ID isused (e.g., group ID=0), or a specific or predetermined group ID valuefor SU-MIMO is used, then the first 3 bits in the Nsts field (thatincludes 9 bits in total in one embodiment, or 12 bits in total inanother embodiment) are used for the number of VHT-LTFs includedtherein, and the other 6 bits (or 9 bits, in an alternative embodiment)can be used to indicate a partial AID (e.g., partial addressinformation) for power saving within SU-MIMO applications.

As mentioned above, power savings of approximately 20% to 48% by earlydetection (e.g., using PHY header information) may be achieved. For theconvenience of the reader, the equation employed for calculating suchfor power saving comparisons:

$R_{TMTS} = \frac{T_{M}}{T_{S}}$ $R_{TSTM} = \frac{T_{S}}{T_{M}}$$R_{TPTM} = \frac{T_{P}}{T_{M}}$ $R_{PRPS} = \frac{P_{R}}{P_{S}}$$\begin{matrix}{\frac{P_{sig}}{P_{mRA}} = \frac{{T_{s} \times P_{R}} + {\left( {T_{P} + T_{M} - T_{S}} \right) \times P_{S}}}{{T_{M} \times P_{R}} + {T_{P} \times P_{S}}}} \\{= \frac{{\frac{T_{M}}{R_{TMTS}} \times P_{s} \times R_{PRPS}} + {\left( {{T_{M} \times R_{TPTM}} + T_{M} - \frac{TM}{R_{TMTS}}} \right) \times P_{S}}}{{T_{M} \times P_{s} \times R_{PRPS}} + {T_{M} \times R_{TPTM} \times P_{S}}}} \\{= \frac{\frac{R_{PRPS}}{R_{TMTS}} + R_{TPTM} + 1 - \frac{1}{R_{TMTS}}}{R_{PRPS} + R_{TPTM}}} \\{= \frac{{R_{TSTM} \times R_{PRPS}} + R_{TPTM} + 1 - R_{TSTM}}{R_{PRPS} + R_{TPTM}}}\end{matrix}$

FIG. 18 is a diagram illustrating an embodiment of a packet in which aPHY portion (e.g., header) thereof includes information indicatingpacket recipients. This embodiment generally shows a packet beingpartitioned into a PHY portion and MAC portion, that is a PHY header anda PHY payload. Generally speaking, the PHY portion of the packet has arelatively more robust character to ensure that all receiving wirelesscommunication devices (e.g., legacy wireless communication devices,those wireless communication devices operative in accordance with newercommunication protocols, etc.) can receive, demodulate, decode, etc. theinformation included in the PHY portion (e.g., header) of the packet. Assuch, all wireless communication devices within a communication systemthat receive such a packet will be able to process the PHY portionthereof thereby determining the recipient list. The MAC portion (PHYpayload) of the packet might be transmitted using a less robustcharacter, and it is therefore less likely to be received, demodulated,decoded, etc. by all recipients.

There are many ways to effectuate such relatively higher robustness forthe PHY portion of the packet (e.g., using a less complex errorcorrection code (ECC), using a lower code rate, using lowered orderedmodulations [e.g., BPSK being lowered order than QPSK, QPSK beinglowered order than 16 QAM, 16 QAM being lowered order than 64 QAM, 64QAM being lowered order than 32 APSK, etc.], using cyclic redundancycheck (CRC) for the PHY portion, etc.).

Information within the PHY portion may be used to indicate the recipientlist (e.g., those receiving wireless communication devices (e.g., STAs)for which the multi-user packet is intended). In some instance, thatsame information (and/or additional information) within the PHY portionmay be used to indicate respective fields within the multi-user packetthat are intended for respective receiving wireless communicationdevices (e.g., STAs). It is of course noted that certain fields may beintended for more than one receiving wireless communication device(e.g., STA). As described elsewhere herein, group ID is one such optionby which such information may be included within the PHY header of amulti-user packet.

FIG. 19 is a diagram illustrating an embodiment of various groupidentification fields being transmitted to one or more receivingwireless communication devices. A group definition field (GDF) may bedefined as a group ID (e.g., y bits, where y is an integer) is used tospecify a group of n MU-MIMO users in a specified order. The group ID isdefined by the transmitting wireless communication device (e.g., AP) andis communicated to the receiving wireless communication devices (e.g.,STAs). The GroupID is assigned by a transmitting wireless communicationdevice (e.g., AP) and is then informed to the respective receivingwireless communication devices (e.g., STAs), either when such receivingwireless communication devices (e.g., STAs) join the basic services set(BSS) or when GroupID assignment is updated by a management frame sentby AP. The management frame employed to update/manage the GroupIDassignment can be either a Broadcast frame or a Unicast frame. The groupID may be transmitted within the body of a management frame that maytake any of a variety of formats including MU-MIMO, OFDMA,MU-MIMO/OFDMA, etc.

For example, such a management frame may be a multi-cast sounding frame(e.g., as described elsewhere herein), a non-sounding frame, or aunicast frame in the format of either sounding or non-sounding frame. Inone embodiment, a management frame without sounding (non-sounding type)may be used to indicate an AID list (e.g., AID=STA identifier, such asan 11-bit association identifier AID) for a group ID without requestinga channel measurement feedback frame (e.g., when the management frametransmitter already has channel state information (CSI)). A group ID ismodified or created by transmitting a group-definition-field. Until asubsequent group-definition-field is received, the last receivedgroup-definition-field is used to interpret and analyze any receivedgroup ID. In some instances where the group ID may be overloaded, thetransmitting wireless communication device (e.g., AP) may assign thesame group ID to different sets of users. For example, even though agroup ID might contain y bits, allowing for 2^(y) (or 2^y) distinctgroup ID values, each such group ID might represent multiple uniquegroupings of receiving wireless communication devices (e.g., STAs). Eachreceiving wireless communication device can be a member of up to 2^(y)(or 2^y) groups, where y is an integer representing the number of bitsin the group ID.

The group definition field (GDF) may be defined as follows: n number ofMU-MIMO users per group (n=4 for example). Also, several GDFs may betransmitted in one management or sounding frame (e.g., for specifyingdifferent groups of users, etc.). Another field within the transmissionmay be used to indicate how many GDFs are included in the management orsounding frame. Upon reception of GDF, each of the receiving wirelesscommunication devices (e.g., STAs) knows its own respective number (STAnumber), such as from 1-4 in this embodiment) associated with group IDthat is defined by the GDF. This STA number indicates the position inthe PHY header of the designated long training field (LTF) for that STAif the STA belongs to the groupID that is found in the VHT-SIG-A fieldof the PHY header.

Within the various diagrams and embodiments described and depictedherein, wireless communication devices may generally be referred to asWDEVs. It is noted that such wireless communication devices may bewireless stations (STAs), access points (APs), or any other type ofwireless communication device without departing from the scope andspirit of the invention. The reference numeral convention associatedwith FIG. 16 (e.g., wireless communication device 1601 generallyperforming operations which may be associated with transmitting wirelesscommunication devices such as APs, and other wireless communicationdevices 1602 a, 1602 b, 1602 c, etc. generally performing operationswhich may be associated with receiving wireless communication devicessuch as STAs) is employed within various other diagrams for ease ofillustration and understanding for the reader in providing a relativelyanalogous context in which various types of communications may occur.

Of course, it is noted that the general nomenclature employed hereinwherein a transmitting wireless communication device (e.g., such asbeing an AP, or a STA operating as an ‘AP’ with respect to other STAs)initiates communications, and/or operates as a network controller typeof wireless communication device, with respect to a number of other,receiving wireless communication devices (e.g., such as being STAs), andthe receiving wireless communication devices (e.g., such as being STAs)responding to and cooperating with the transmitting wirelesscommunication device in supporting such communications. Of course, whilethis general nomenclature of transmitting wireless communicationdevice(s) and receiving wireless communication device(s) may be employedto differentiate the operations as performed by such different wirelesscommunication devices within a communication system, all such wirelesscommunication devices within such a communication system may of coursesupport bi-directional communications to and from other wirelesscommunication devices within the communication system. In other words,the various types of transmitting wireless communication device(s) andreceiving wireless communication device(s) may all supportbi-directional communications to and from other wireless communicationdevices within the communication system.

FIG. 20 is a diagram illustrating an embodiment of communicationsbetween various wireless communication devices within a communicationsystem. Within this diagram, wireless communication device 2001 isoperative to perform transmitting of a group definition field and/or agroup identification field (group ID) look up table (LUT) to a pluralityof wireless communication devices (shown as wireless communicationdevices 2002 a, 2002 b, 2002 c, etc.). The group ID LUT may be viewed asbeing a table that provides a very efficient representation between thevarious subsets of the wireless communication devices (or users) andgroup IDs. For example, each respective group ID within the group ID LUTmay correspond to one or more subsets of the wireless communicationdevices. When a particular wireless communication device is includedwithin multiple respective subsets, it is located within a commonlocation within each of those subsets. For example, if the wirelesscommunication device 2002 a is located in a given location (e.g., thesecond location) within a particular subset, then that same wirelesscommunication device 2002 a is located within the same location (e.g.,the second location) within all other subsets that include that samewireless communication device 2002 a as well.

It is noted that the various wireless communication devices within acommunication system employ a common group ID LUT when operatingcooperatively with one another. That is to say, for coordinatedoperation in accordance with using the very efficient manner ofassociating various group IDs and wireless communication devices (orusers), the various wireless communication devices all respectively needto have access to the common group ID LUT. In embodiments in which thegroup ID LUT may be modified or updated (e.g., as a function of timesuch as every X number of seconds, after a particular event occurs, orbased on some other consideration, etc.), then all of the variouswireless communication devices should be employing the most recent orcurrent, common group ID LUT for coordinated operation.

After the wireless communication device 2001 transmits the groupdefinition field and/or the group ID LUT to the plurality of wirelesscommunication devices (e.g., such as shown at time 1), then the wirelesscommunication device 2001 operates by transmitting a multi-user packetto the plurality of wireless communication devices (e.g., such as shownat time 2). Such a multi-user packet may be communicated in accordancewith orthogonal frequency division multiple access (OFDMA) signaling,multi-user multiple input multiple output (MU-MIMO) signaling, acombination thereof (such as OFDMA/MU-MIMO), etc. Such a multi-userpacket includes at least one group ID therein that indicates, based onthe group definition field or the group ID LUT, a first field of themulti-user packet to be processed by a first of the plurality ofwireless communication devices (e.g., wireless communication device 2002a) and a second field of the multi-user packet to be processed by asecond of the plurality of wireless communication devices (e.g., bywireless communication device 2002 b). For example, in certainembodiments, the first field of the multi-user packet to be processedwould be the group ID.

As mentioned, any one group ID may corresponds to more than one subsetof the plurality of wireless communication devices, a conditionpreviously described as overloading of group IDs. As will be seenelsewhere herein, a group ID may correspond to as few as one subset ofwireless communication devices, or alternatively, to a plurality ofsubsets of wireless communication devices (e.g., to a first subset ofwireless communication devices, and also to a second subset of wirelesscommunication devices, etc.).

Also, based on the group ID, at least one additional field within themulti-user packet indicates a first at least one space-time stream (STS)within the multi-user packet corresponding to the first of the pluralityof wireless communication devices and a second at least one STS withinthe multi-user packet corresponding to a second of the plurality ofwireless communication devices. That is to say, when a given multi-userpacket does in fact correspond to a given wireless communication device,then further details are provided to indicate which particular one ormore STSs employed and corresponding to that particular wirelesscommunication device. For example, within an N_sts field of acommunication received from the wireless communication device 2001, agiven recipient wireless communication device that is included within atleast one subset of wireless communication devices corresponding to thegroup ID, may consider the N_sts field in accordance with identifying anon-zero value therein to indicate which particular STSs correspond tothat recipient wireless communication device.

FIG. 21 is an alternative diagram illustrating an embodiment ofcommunications between various wireless communication devices within acommunication system. This diagram shows different means by whichdifferent groups of wireless communication devices may be indicated by agroup ID (such as included within a multi-user packet or othercommunication provided from wireless communication device 2101) toindicate that the communication is intended for that group of wirelesscommunication devices.

In this embodiment, each respective subset of wireless communicationdevices includes up to 4 wireless communication devices. When thewireless communication device 2101 desires to provide a communicationcorresponding to more than 4 wireless communication devices, a singlegroup ID can operate in accordance with overloading. That is to say,such a group ID may correspond to at least two subsets of wirelesscommunication devices that, when considered together, include these morethan 4 wireless communication devices.

Looking particularly at the embodiment of this diagram, the wirelesscommunication device 2101 desires to provide one or more multi-userpackets to some, but not all, of the wireless communication devices 2102a, 2102 b, 2102 c, 2102 d, 2102 e, 2102 f, 2102 g, 2102 h, etc. (i.e.,specifically only to wireless communication devices 2102 a, 2102 c, 2102d, 2102 f, 2102 g, 2102 h, etc. in this embodiment). When considering asituation in which no more than 4 wireless communication devices areincluded within any one subset and no more than one group ID value isprovided within a single multi-user (MU) packet, then a variety ofsubset combinations may be associated with a group ID to indicatecommunications to such a group of wireless communication devices(including more than 4 wireless communication devices) for eachtransmitted multi-user packet. Some examples are provided: an option 1includes two subsets [a, c, d, f] and [h, g, d, f]; an option 2 includesthree subsets [a, c, d, f], [a, c, d, g], and [a, c, d, h].

For example, the subset [a, c, d, f] corresponds to wirelesscommunication devices 2102 a, 2102 c, 2102 d, and 2102 f. The subset [h,g, d, f] corresponds to wireless communication devices 2102 h, 2102 g,2102 d, and 2102 f. The inclusion of wireless communication deviceswithin other of the subsets may be understood analogously by the reader.As may be seen, when a given wireless communication device is includedwithin more than one particular subset, it is located within the samelocation within each of those particular subsets.

FIG. 22, FIG. 23, FIG. 24A, and FIG. 24B illustrate embodiments ofmethods for operating wireless communication devices.

Referring to method 2200 of FIG. 22, the method 2200 begins by operatinga first wireless communication device by employing at least one antennafor receiving a multi-user packet from a second wireless communicationdevice, the multi-user packet including a PHY header for selectivelyindicating the multi-user packet is intended for at least one of thefirst wireless communication device and another wireless communicationdevice (e.g., a third wireless communication device), as shown in ablock 2210.

The method 2200 continues by processing the PHY header for determiningif the multi-user packet is intended for the first wirelesscommunication device, as shown in a block 2220. It is of course notedthat, while the generic term of multi-user packet is employed in manycontexts and embodiment herein, a ‘multi-user packet’ may be intendedfor as few as a single receiving wireless communication device withoutdeparting from the scope and spirit of the invention. For example, sucha ‘multi-user packet’ may have a format corresponding to and complyingwith a MU context, where such a ‘multi-user packet’ may be intended fora SU context. However, the generic term of multi-user packet is employedherein to describe such a packet having the characteristics, structure,etc. described herein though such a packet may be intended for as few asa single receiving wireless communication device.

The method 2200 then operates by processing a field within themulti-user packet following the PHY header and corresponding to thefirst wireless communication device as indicated in the PHY header whenthe multi-user packet is intended for the first wireless communicationdevice, as shown in a block 2230. That is to say, when the multi-userpacket is in fact intended for the first wireless communication deviceas based on the operations in the block 2220, the method 2200 mayoperate by then processing at least one particular field within themulti-user packet that is intended for the first wireless communicationdevice. Such at least one field(s) may be indicated as well within thePHY header portion of the multi-user packet as well.

Alternatively, when the multi-user packet is not intended for the firstwireless communication device as based on the operations in the block2220, the method 2200 continues by terminating processing of themulti-user packet after processing the PHY header when the multi-userpacket is not intended for the first wireless communication device, asshown in a block 2240. Such operations in accordance with the method2200 may generally be viewed as being performed within a receivingwireless communication device (e.g., STA).

Referring to method 2300 of FIG. 23, the method 2300 begins by operatinga first wireless communication device by employing at least one antennafor receiving a multi-user packet from a second wireless communicationdevice, the multi-user packet including a PHY header, encoded withcyclic redundancy check (CRC), for selectively indicating the multi-userpacket is intended for at least one of the first wireless communicationdevice and a third wireless communication device, as shown in a block2310.

The method 2300 continues by processing a signal field within the PHYheader, located at a beginning of a non-legacy portion of the PHYheader, for determining if the multi-user packet is intended for thefirst wireless communication device, as shown in a block 2320.

When the multi-user packet is in fact intended for the first wirelesscommunication device as based on the operations in the block 2320, themethod 2300 may operate by then processing a field within the multi-userpacket following the PHY header corresponding to the first wirelesscommunication device and as indicated in the PHY header, as shown in ablock 2330.

Alternatively, when the multi-user packet is not intended for the firstwireless communication device as based on the operations in the block2320, the method 2300 continues by terminating processing of themulti-user packet after processing the PHY header, as shown in a block2340.

In some instances, the PHY header of the multi-user packet has beenencoded with at least one modulation coding parameter being relativelymore robust than at least one additional modulation coding parameter bywhich the remainder of the multi-user packet encoded, noting that thePHY header and the remainder of the multi-user packet may be encodedwith different respective operational parameters (e.g., modulations,code rates, etc.). That is to say, the PHY header has been encoded withrespective parameters that are relatively more robust than those bywhich the remainder of the multi-user packet has been encoded. Suchoperations in accordance with the method 2300 may generally be viewed asbeing performed within a receiving wireless communication device (e.g.,STA).

Referring to method 2400 of FIG. 24A, the method 2400 begins bygenerating a multi-user packet with PHY header including intendedrecipient information (e.g., indicating for which wireless communicationdevices multi-user packet intended), as shown in a block 2410. Incertain embodiments, PHY header may include information indicating whichfields of multi-user packet are respectively intended for which wirelesscommunication devices, as shown in a block 2410 a. The method 2400continues by transmitting the multi-user packet to a plurality ofwireless communication devices, as shown in a block 2420. Suchoperations in accordance with the method 2400 may generally be viewed asbeing performed within a transmitting wireless communication device(e.g., AP or a STA operating in accordance with AP functionality).

Referring to method 2401 of FIG. 24B, the method 2401 begins byreceiving a multi-user packet, as shown in a block 2411. The method 2401then operates by processing a PHY header of the multi-user packet todetermine if the wireless communication device is an intended recipientof the multi-user packet, as shown in a block 2421. The method 2401continues by determining if the multi-user packet is intended for thewireless communication device, as shown in a decision block 2431.

If the multi-user packet is intended for the wireless communicationdevice, the method 2401 then operates by processing the PHY header ofthe multi-user packet to determine field(s) intended for wirelesscommunication device, as shown in a block 2441. The method 2401 thencontinues by processing field(s) intended for wireless communicationdevice, as shown in a block 2451.

Alternatively, if the multi-user packet is intended for the wirelesscommunication device, the method 2401 then operates by performing powersavings operations (e.g., dropping multi-user packet, ceasing processingof multi-user packet, power down, entering sleep mode, etc.), as shownin a block 2461. Such operations in accordance with the method 2401 maygenerally be viewed as being performed within a receiving wirelesscommunication device (e.g., STA).

It is also noted that the various operations and functions as describedwith respect to various methods herein may be performed within awireless communication device, such as using a baseband processingmodule implemented therein, (e.g., such as in accordance with thebaseband processing module as described with reference to FIG. 2). Forexample, such a baseband processing module can perform such processing(e.g., either the generating and/or receive processing) of recipientlist information (and/or respective field related information) of PHYheader information within a packet and/or any other operations andfunctions as described herein, etc. or their respective equivalents.

FIG. 25 is a diagram illustrating an embodiment of signal field bitallocation as may be employed within communications between wirelesscommunication devices in accordance with multi-user (MU) applications.Considering such a possible variant to signal field bit allocation, if abit is employed therein for smoothing, it should be located in the firstsignal field (VHT-SIGA) to estimate the communication channel via whichthe packet is received with at least one VHT-LTF. In embodiments thatmay employ space time block coding (STBC), an STBC bit may be employedin the first signal field (VHT-SIGA). In some instances, 1 bit of STBCindication may be sufficient. The various fields such asDuration/BW/SGI/Smoothing/STBC/MU bits/GrpID (group ID) are employed todeliver common information across all users (e.g., legacy and non-legacyreceiving wireless communication devices). The Nsts Table Indexindicates the number of the space-time streams for each user. When anon-sounding bit is employed in the second signal field (VHT-SIGB), atransmitting wireless communication device (e.g., AP) may want torequest an update of channel state information (CSI) for a only subsetof the receiving wireless communication devices (e.g., STAs).

As mentioned elsewhere herein, such multi-user packets having structureand format in accordance with the principles presented herein and may beadapted for both MU and SU applications.

When operating in accordance with a MU context, resolvable ornon-resolvable LTFs may be employed (more details of which are describedbelow, and also as described in U.S. Utility patent application Ser. No.12/796,655, entitled “Group identification and definition withinmultiple user, multiple access, and/or MIMO wireless communications,”which has been incorporated by reference above). The use ofnon-resolvable LTFs may have limited usage due to channel variation, butit may have benefits in accordance with the use of short packets (e.g.,less overhead).

If the non-resolvable LTFs option is desired in a particular context,implementation flexibility may be provided with a restriction that thesame number of LTFs is send to all receiving wireless communicationdevices (e.g., STAs). For example, if the group ID=0 for non-resolvableLTFs, or a specific or predetermined value, for SU-MIMO non-resolvableLTFs, then all receiving wireless communication devices (e.g., STAs) canassume that a preamble contains a number of LTFs indicated for a firstrespective receiving wireless communication device (e.g., STA) (e.g.,Nsts_(—)1 determines number of LTFs). The number of LTFs may be set tobe the max(LTFs over all STAs). If the actual number of space-timestreams, Nsts_k, <Nsts_(—)1 for a certain receiving wirelesscommunication device (e.g., STA), that receiving wireless communicationdevice (e.g., STA) may ignore the channel measured from LTFn, wheren>Nsts_k and k=1, . . . , 4 users (for example).

If the non-resolvable LTFs option is desired to be allowed in aparticular context so that each respective receiving wirelesscommunication device (e.g., STA) may have a different number of LTFs,and the group ID and Nsts field may indicate how many LTFs correspond toeach respective receiving wireless communication device (e.g., STA)(e.g., such as when a management frame exchange is performed).

In order to avoid any performance degradation, it may be recommended touse non-resolvable LTFs for only a limited number or types of cases. Forexample, non-resolvable LTFs may be limited only to applications thatmay get better performance gain over resolvable LTFs. Also, it is notedthat, in order to make signaling more straightforward, a “resolvableLTF” bit may be included that indicates resolvable application or thenon-resolvable LTFs application.

FIG. 26 is a diagram illustrating an embodiment of signal field bitallocation as may be employed within communications between wirelesscommunication devices in accordance with single-user (SU) applications.As may be seen with respect to this diagram, this can have the samestructure of bit allocation when compared with MU. The Nsts fielddetermines the number of VHT-LTFs (1 to 8) using the first 3 bits in theNsts Table Index. In the second signal field (VHT-SIGB), modulationcoding set (MCS) bits may be extended to 6 (or up to 8) bits to supportunequal modulation using reserved bits in MU; this will not change thedefinition of other bits in the second signal field (VHT-SIGB). Reservedbits in the first signal field (VHT-SIGA) may then be 7 (or 8) bits.These bits may be used for a number of applications, including using 2more bits for STBC to cover 8 transmit antennas, and/orcoding/non-sounding bits may be moved (or copied) from the second signalfield (VHT-SIGB) if necessary. Alternatively, 11 bits of STA ID (SID)(by combining group ID) may be used for such applications as mentionedabove.

FIG. 27 is a diagram illustrating an alternative embodiment of signalfield bit allocation as may be employed within communications betweenwireless communication devices. A resolvable LTF bit in combination withNsts field may be employed to indicate whether the packet is SU/MU withresolvable LTFs or not.

When the resolvable LTF bit in combination with Nsts field is set to 1,LTFs are resolvable, a configuration which can be used for SU-MIMO orMU-MIMO with non-resolvable LTFs; # of LTFs=sum(LTFs_k), k=1, 2, 3 and4.

When operating in accordance with a SU-MIMO application context, theNsts field may be as follows: Nsts=[0 8 0 0]. For example, one non-zeroentry in the Nsts field indicates SU-MIMO operation. After collectingchannel state information (CSI) following the transmission of asounding/management frame, a transmitting wireless communication device(e.g., AP) may choose to operate in accordance with SU-MIMO with groupID indication in the preamble that may enable power save mode fordevices that are not recipients of the packet. If the transmittingwireless communication device (e.g., AP) desires to operate inaccordance with an open loop transmission (e.g., without exchange of amanagement frame), then group ID is set to 0, or a specific orpredetermined value, and only the first 3 bits in Nsts may then be usedto indicate the number of LTFs. It is noted that Nsts and number of LTFsmay be related such that Nsts=3 may require 4 LTFs, in one possibleembodiment. It is still possible to reuse the upper 6 bits (or 9 bits,in an alternative embodiment) in Nsts Table Index when group ID=0 (or aspecific or predetermined value).

Alternatively, when operating in accordance with a MU-MIMO applicationcontext, the group ID may be used to indicate the number of valid LTFsfor each respective receiving wireless communication device (e.g., STA)in the Nsts field. The group ID indication in the preamble may enablepower save mode for devices that are not recipients of the packet (e.g.,for those not included within the recipient list information includedwithin the PHY header information of a packet, such as the group ID).

Power saving can be also achieved with MU-MIMO packets. When group ID isset to one of groups for MUMIMO, all the other receiving wirelesscommunication devices (e.g., STAs) that do not belong to the specifiedgroup do not have to decode the packet further, since they detects thedestination of the packet is not for them by reading the group ID. Then,they can drop the packet earlier before decoding MAC header. However, ifthey belong to the specified group ID, they need to decode how many ofthe respective streams (e.g., number of space-time streams) are assignedto them by reading Nsts field in the preamble. If there are no streamsthat are assigned to them, they can drop the packet earlier beforedecoding MAC header. Otherwise, they have to process all of theremainder packet to its end.

For example, consider an embodiment in which group ID=5 is defined forSTA=[A C F E] in the order. When the packet with group ID=5 is sent, STAB does not have to decode the packet after VHT-SIGA, since it knows itdoes not belong to the group ID=5. Only the respective STAs A, C,F,Eneed to decode the packet. They read Nsts field in VHT-SIGA to determinewhich streams particularly to process (e.g., if Nsts=[0 3 2 0], then thenumber of streams assigned to STA_[A C F E] is [0 3 2 0]). In such aninstance, since there is no stream assigned to STA A, STA A does notneed to decode the packet further, so it drops the packet right afterVHT-SIGA. The same operations may be performed for STA E. However, STA Cand STA F, which have the number of streams assigned with 3 and 2,respectively, need to decode the whole packet. Therefore, all STAsexcept for STA C and STA F in the basic services set (BSS) do not haveto decode the whole packet and can drop the packet earlier, therebysaving unnecessary power.

When the resolvable LTF bit in combination with Nsts field is set to 0,then the LTFs used for MU-MIMO are non-resolvable, and the number ofLTFs=max(LTFs_k). Considering the MU-MIMO application context, group IDcan be still used if a transmitting wireless communication device (e.g.,AP) has such capability and if a valid number of LTFs for eachrespective receiving wireless communication device (e.g., STA) isindicated in the Nsts field (e.g., after the SIGA field after group ID).Again, PHY header information such as a group ID indication in thepreamble may enable power save mode for those receiving wirelesscommunication devices (e.g., STAs) that are not recipients of thepacket. If the transmitting wireless communication device (e.g., AP)does not have such capability (e.g., group ID), then the group ID may beset to 0, and only the first 3 bits in the Nsts field are used toindicate the number of LTFs. Again, it is still possible to reuse theupper 6 bits in Nsts Table Index when the group ID=0 (or specific orpredetermined value).

When operating in accordance with a SU-MIMO application context based onthis variant, when a recipient wireless communication device (e.g., STA)is not in the list of any group ID (e.g., when operating in accordancewith an open loop mode without a management frame exchange, such as whengroup ID=0, or specific or predetermined value). When the resolvable LTFbit is set to 1 (e.g., in order to distinguish from non-resolvable LTFsfor MU-MIMO), then only the bits, b0 to b2, in Nsts field are used, andan extra 6 bits (or 9 bits, in an alternative embodiment) are availablefor an alternative use or new definition.

However, when a recipient wireless communication device (e.g., STA) isin the list of a group ID, then the resolvable LTF bit=1 (or 0). In suchan embodiment, a non-zero group ID and all 9 bits (or 12 bits) in theNsts field may be used to indicate the number of streams for up to 4users, but only one Nsts_k is non-zero.

When operating in accordance with a MU-MIMO application context based onthis variant, when non-resolvable LTFs are being used (e.g., theresolvable LTF bit=0), then if the group ID is non-zero, all 9 bits (or12 bits) in the Nsts field are used, and the number of VHT-LTFs in thePHY header is equal to Max_k(LTFs_k), where k=1, 2, 3, 4. Eachrespective receiving wireless communication device (e.g., STA) stillknows the exact Nsts field for itself (e.g., by detecting Nsts_k). Ifgroup ID=0 (or specific or predetermined value), only b0˜b2 in Nstsfield are used to indicate the number of space-time streams directedtoward the recipient in the transmission leaving an extra 6 bits (or 9bits, in an alternative embodiment) available for an alternative use ornew definition.

When operating in accordance with a MU-MIMO application context based onthis variant, the resolvable LTFs are used (e.g., resolvable LTF bit=1),and if a non-zero group ID is indicated then all 9 bits (or 12 bits) inthe Nsts field are used to indicate he number os space-time streamsdirected towards each recipient in this transmission, and the number ofVHT-LTFs=sum(LTFs_k), where k varies from k=0 to k=n, where n is thenumber of receiving wireless communication devices (e.g., STAs) includedwithin the intended recipient list for the MU transmission.

It is noted that a non-zero group ID can be used to AID in power savingfor non-recipient STAs through early packet drop. Also, in order to makesignaling more straightforward, a MU bit may be included that indicateswhether the particular packet corresponds to a MU or SU application.

FIG. 28 is a diagram illustrating yet another alternative embodiment ofsignal field bit allocation as may be employed within communicationsbetween wireless communication devices. This embodiment does not includethe MU indication bit (such as is included in other embodiments herein).Nonetheless, another option may be employed to indicate whether theparticular packet corresponds to a MU or SU application, such as usingthe Nsts field.

For example, if the Nsts field includes only one non-zero entry (e.g.,Nsts=[0 8 0 0]), then the packet actually corresponds to a SU-MIMOapplication. After collecting CSI by employing a sounding/managementframe with a non-zero group ID, a transmitting wireless communicationdevice (e.g., AP) may choose to operate in accordance with SU-MIMO withthe same group ID (e.g., such as may be used for power saving purposes)and then by providing only one non-zero entry in the Nsts field asdescribed above. If the transmitting wireless communication device(e.g., AP) desires to operate in accordance with an open looptransmission scheme, the management frame can be sent without requestingCSI feedback and a non-zero group ID field may be included in thepreamble of the transmitted packet.

For Non-resolvable LTFs employed in accordance with a MU application orin accordance with an open loop SU application operating without amanagement frame exchange, the group ID may be set to 0 and the first 3bits in Nsts may be used to indicate the number of LTFs so that it ispossible to allocate the upper 6 bits (or 9 bits, in an alternativeembodiment) in the Nsts Table Index to indicate a partial MAC addressfor SU-MIMO and these bits can then be used to enhance the ability oflistening STAs to save power.

As may be seen in accordance with the various principles and aspects ofthe invention, one unified format of bit definition for SU and MU-MIMOmay be employed with a slight bit definition change. Even with respectto the SU-MIMO or non-resolvable LTFs MU case, group ID (or SID) may beused to save power for STAs.

It is noted that the various modules and/or circuitries (e.g., basebandprocessing modules, encoding modules and/or circuitries, decodingmodules and/or circuitries, etc., etc.) described herein may be a singleprocessing device or a plurality of processing devices. Such aprocessing device may be a microprocessor, micro-controller, digitalsignal processor, microcomputer, central processing unit, fieldprogrammable gate array, programmable logic device, state machine, logiccircuitry, analog circuitry, digital circuitry, and/or any device thatmanipulates signals (analog and/or digital) based on operationalinstructions. The operational instructions may be stored in a memory.The memory may be a single memory device or a plurality of memorydevices. Such a memory device may be a read-only memory (ROM), randomaccess memory (RAM), volatile memory, non-volatile memory, staticmemory, dynamic memory, flash memory, and/or any device that storesdigital information. It is also noted that when the processing moduleimplements one or more of its functions via a state machine, analogcircuitry, digital circuitry, and/or logic circuitry, the memory storingthe corresponding operational instructions is embedded with thecircuitry comprising the state machine, analog circuitry, digitalcircuitry, and/or logic circuitry. In such an embodiment, a memorystores, and a processing module coupled thereto executes, operationalinstructions corresponding to at least some of the steps and/orfunctions illustrated and/or described herein.

It is also noted that any of the connections or couplings between thevarious modules, circuits, functional blocks, components, devices, etc.within any of the various diagrams or as described herein may bedifferently implemented in different embodiments. For example, in oneembodiment, such connections or couplings may be direct connections ordirect couplings there between. In another embodiment, such connectionsor couplings may be indirect connections or indirect couplings therebetween (e.g., with one or more intervening components there between).Of course, certain other embodiments may have some combinations of suchconnections or couplings therein such that some of the connections orcouplings are direct, while others are indirect. Differentimplementations may be employed for effectuating communicative couplingbetween modules, circuits, functional blocks, components, devices, etc.without departing from the scope and spirit of the invention.

As one of average skill in the art will appreciate, the term“substantially” or “approximately”, as may be used herein, provides anindustry-accepted tolerance to its corresponding term. Such anindustry-accepted tolerance ranges from less than one percent to twentypercent and corresponds to, but is not limited to, component values,integrated circuit process variations, temperature variations, rise andfall times, and/or thermal noise. As one of average skill in the artwill further appreciate, the term “operably coupled”, as may be usedherein, includes direct coupling and indirect coupling via anothercomponent, element, circuit, or module where, for indirect coupling, theintervening component, element, circuit, or module does not modify theinformation of a signal but may adjust its current level, voltage level,and/or power level. As one of average skill in the art will alsoappreciate, inferred coupling (i.e., where one element is coupled toanother element by inference) includes direct and indirect couplingbetween two elements in the same manner as “operably coupled”. As one ofaverage skill in the art will further appreciate, the term “comparesfavorably”, as may be used herein, indicates that a comparison betweentwo or more elements, items, signals, etc., provides a desiredrelationship. For example, when the desired relationship is that signal1 has a greater magnitude than signal 2, a favorable comparison may beachieved when the magnitude of signal 1 is greater than that of signal 2or when the magnitude of signal 2 is less than that of signal 1.

Various aspects of the present invention have also been described abovewith the aid of method steps illustrating the performance of specifiedfunctions and relationships thereof. The boundaries and sequence ofthese functional building blocks and method steps have been arbitrarilydefined herein for convenience of description. Alternate boundaries andsequences can be defined so long as the specified functions andrelationships are appropriately performed. Any such alternate boundariesor sequences are thus within the scope and spirit of the claimedinvention.

Various aspects of the present invention have been described above withthe aid of functional building blocks illustrating the performance ofcertain significant functions. The boundaries of these functionalbuilding blocks have been arbitrarily defined for convenience ofdescription. Alternate boundaries could be defined as long as thecertain significant functions are appropriately performed. Similarly,flow diagram blocks may also have been arbitrarily defined herein toillustrate certain significant functionality. To the extent used, theflow diagram block boundaries and sequence could have been definedotherwise and still perform the certain significant functionality. Suchalternate definitions of both functional building blocks and flowdiagram blocks and sequences are thus within the scope and spirit of theclaimed invention.

One of average skill in the art will also recognize that the functionalbuilding blocks, and other illustrative blocks, modules and componentsherein, can be implemented as illustrated or by discrete components,application specific integrated circuits, processors executingappropriate software and the like or any combination thereof.

Moreover, although described in detail for purposes of clarity andunderstanding by way of the aforementioned embodiments, various aspectsof the present invention are not limited to such embodiments. It will beobvious to one of average skill in the art that various changes andmodifications may be practiced within the spirit and scope of theinvention, as limited only by the scope of the appended claims.

Mode Selection Tables:

TABLE 1 2.4 GHz, 20/22 MHz channel BW, 54 Mbps max bit rate Code RateModulation Rate NBPSC NCBPS NDBPS EVM Sensitivity ACR AACR 1 Barker BPSK2 Barker QPSK 5.5 CCK 6 BPSK 0.5 1 48 24 −5 −82 16 32 9 BPSK 0.75 1 4836 −8 −81 15 31 11 CCK 12 QPSK 0.5 2 96 48 −10 −79 13 29 18 QPSK 0.75 296 72 −13 −77 11 27 24 16-QAM 0.5 4 192 96 −16 −74 8 24 36 16-QAM 0.75 4192 144 −19 −70 4 20 48 64-QAM 0.666 6 288 192 −22 −66 0 16 54 64-QAM0.75 6 288 216 −25 −65 −1 15

TABLE 2 Channelization for Table 1 Frequency Channel (MHz) 1 2412 2 24173 2422 4 2427 5 2432 6 2437 7 2442 8 2447 9 2452 10 2457 11 2462 12 2467

TABLE 3 Power Spectral Density (PSD) Mask for Table 1 PSD Mask 1Frequency Offset dBr     −9 MHz to 9 MHz 0 +/−11 MHz −20 +/−20 MHz −28+/−30 MHz and −50 greater

TABLE 4 5 GHz, 20 MHz channel BW, 54 Mbps max bit rate Code RateModulation Rate NBPSC NCBPS NDBPS EVM Sensitivity ACR AACR 6 BPSK 0.5 148 24 −5 −82 16 32 9 BPSK 0.75 1 48 36 −8 −81 15 31 12 QPSK 0.5 2 96 48−10 −79 13 29 18 QPSK 0.75 2 96 72 −13 −77 11 27 24 16-QAM 0.5 4 192 96−16 −74 8 24 36 16-QAM 0.75 4 192 144 −19 −70 4 20 48 64-QAM 0.666 6 288192 −22 −66 0 16 54 64-QAM 0.75 6 288 216 −25 −65 −1 15

TABLE 5 Channelization for Table 4 Frequency Frequency Channel (MHz)Country Channel (MHz) Country 240 4920 Japan 244 4940 Japan 248 4960Japan 252 4980 Japan 8 5040 Japan 12 5060 Japan 16 5080 Japan 36 5180USA/Europe 34 5170 Japan 40 5200 USA/Europe 38 5190 Japan 44 5220USA/Europe 42 5210 Japan 48 5240 USA/Europe 46 5230 Japan 52 5260USA/Europe 56 5280 USA/Europe 60 5300 USA/Europe 64 5320 USA/Europe 1005500 USA/Europe 104 5520 USA/Europe 108 5540 USA/Europe 112 5560USA/Europe 116 5580 USA/Europe 120 5600 USA/Europe 124 5620 USA/Europe128 5640 USA/Europe 132 5660 USA/Europe 136 5680 USA/Europe 140 5700USA/Europe 149 5745 USA 153 5765 USA 157 5785 USA 161 5805 USA 165 5825USA

TABLE 6 2.4 GHz, 20 MHz channel BW, 192 Mbps max bit rate ST Code RateTX Antennas Rate Modulation Code Rate NBPSC NCBPS NDBPS 12 2 1 BPSK 0.51 48 24 24 2 1 QPSK 0.5 2 96 48 48 2 1 16-QAM 0.5 4 192 96 96 2 1 64-QAM0.666 6 288 192 108 2 1 64-QAM 0.75 6 288 216 18 3 1 BPSK 0.5 1 48 24 363 1 QPSK 0.5 2 96 48 72 3 1 16-QAM 0.5 4 192 96 144 3 1 64-QAM 0.666 6288 192 162 3 1 64-QAM 0.75 6 288 216 24 4 1 BPSK 0.5 1 48 24 48 4 1QPSK 0.5 2 96 48 96 4 1 16-QAM 0.5 4 192 96 192 4 1 64-QAM 0.666 6 288192 216 4 1 64-QAM 0.75 6 288 216

TABLE 7 Channelization for Table 6 Channel Frequency (MHz) 1 2412 2 24173 2422 4 2427 5 2432 6 2437 7 2442 8 2447 9 2452 10 2457 11 2462 12 2467

TABLE 8 5 GHz, 20 MHz channel BW, 192 Mbps max bit rate ST Code Rate TXAntennas Rate Modulation Code Rate NBPSC NCBPS NDBPS 12 2 1 BPSK 0.5 148 24 24 2 1 QPSK 0.5 2 96 48 48 2 1 16-QAM 0.5 4 192 96 96 2 1 64-QAM0.666 6 288 192 108 2 1 64-QAM 0.75 6 288 216 18 3 1 BPSK 0.5 1 48 24 363 1 QPSK 0.5 2 96 48 72 3 1 16-QAM 0.5 4 192 96 144 3 1 64-QAM 0.666 6288 192 162 3 1 64-QAM 0.75 6 288 216 24 4 1 BPSK 0.5 1 48 24 48 4 1QPSK 0.5 2 96 48 96 4 1 16-QAM 0.5 4 192 96 192 4 1 64-QAM 0.666 6 288192 216 4 1 64-QAM 0.75 6 288 216

TABLE 9 channelization for Table 8 Frequency Frequency Channel (MHz)Country Channel (MHz) Country 240 4920 Japan 244 4940 Japan 248 4960Japan 252 4980 Japan 8 5040 Japan 12 5060 Japan 16 5080 Japan 36 5180USA/Europe 34 5170 Japan 40 5200 USA/Europe 38 5190 Japan 44 5220USA/Europe 42 5210 Japan 48 5240 USA/Europe 46 5230 Japan 52 5260USA/Europe 56 5280 USA/Europe 60 5300 USA/Europe 64 5320 USA/Europe 1005500 USA/Europe 104 5520 USA/Europe 108 5540 USA/Europe 112 5560USA/Europe 116 5580 USA/Europe 120 5600 USA/Europe 124 5620 USA/Europe128 5640 USA/Europe 132 5660 USA/Europe 136 5680 USA/Europe 140 5700USA/Europe 149 5745 USA 153 5765 USA 157 5785 USA 161 5805 USA 165 5825USA

TABLE 10 5 GHz, with 40 MHz channels and max bit rate of 486 Mbps TX STCode Code Rate Antennas Rate Modulation Rate NBPSC 13.5 Mbps  1 1 BPSK0.5 1  27 Mbps 1 1 QPSK 0.5 2  54 Mbps 1 1 16-QAM 0.5 4 108 Mbps 1 164-QAM 0.666 6 121.5 Mbps   1 1 64-QAM 0.75 6  27 Mbps 2 1 BPSK 0.5 1 54 Mbps 2 1 QPSK 0.5 2 108 Mbps 2 1 16-QAM 0.5 4 216 Mbps 2 1 64-QAM0.666 6 243 Mbps 2 1 64-QAM 0.75 6 40.5 Mbps  3 1 BPSK 0.5 1  81 Mbps 31 QPSK 0.5 2 162 Mbps 3 1 16-QAM 0.5 4 324 Mbps 3 1 64-QAM 0.666 6 365.5Mbps   3 1 64-QAM 0.75 6  54 Mbps 4 1 BPSK 0.5 1 108 Mbps 4 1 QPSK 0.5 2216 Mbps 4 1 16-QAM 0.5 4 432 Mbps 4 1 64-QAM 0.666 6 486 Mbps 4 164-QAM 0.75 6

TABLE 11 Power Spectral Density (PSD) mask for Table 10 PSD Mask 2Frequency Offset dBr    −19 MHz to 19 MHz 0 +/−21 MHz −20 +/−30 MHz −28+/−40 MHz and −50 greater

TABLE 12 Channelization for Table 10 Frequency Frequency Channel (MHz)Country Channel (MHz) County 242 4930 Japan 250 4970 Japan 12 5060 Japan38 5190 USA/Europe 36 5180 Japan 46 5230 USA/Europe 44 5520 Japan 545270 USA/Europe 62 5310 USA/Europe 102 5510 USA/Europe 110 5550USA/Europe 118 5590 USA/Europe 126 5630 USA/Europe 134 5670 USA/Europe151 5755 USA 159 5795 USA

What is claimed is:
 1. A method for operating a first wirelesscommunication device, the method comprising: employing at least oneantenna for receiving a group definition from a second wirelesscommunication device, the group definition including a group identifierand a plurality of associate identifiers corresponding to a plurality ofdevices of a group; determining that the first wireless communicationdevice is included in the group based on the group definition bydetermining that an associate identifier corresponding to the firstwireless communication device is included in the plurality of associateidentifiers corresponding to the plurality of devices of the group;determining a position of device specific data associated with the firstwireless communication device, based on the plurality of associateidentifiers included in the group definition; employing the at least oneantenna for receiving a multi-user packet from the second wirelesscommunication device at a time subsequent to receiving the groupdefinition, the multi-user packet including a PHY (physical layer)header having a group identification field (group ID field) thatincludes the group identifier; processing the PHY header to determine ifthe first wireless communication device is included in a plurality ofdevices the multi-user packet is intended for by identifying the groupidentifier in the group ID field; processing the PHY header to extractthe device specific data from the PHY header, based on the position ofthe device specific data; processing a field within the multi-userpacket following the PHY header corresponding to the first wirelesscommunication device and as indicated in the PHY header when themulti-user packet is intended for the first wireless communicationdevice; and terminating processing of the multi-user packet afterprocessing the PHY header when the multi-user packet is not intended forthe first wireless communication device.
 2. The method of claim 1,wherein: the multi-user packet being a multi-user multiple inputmultiple output (MU-MIMO) packet or an orthogonal frequency divisionmultiple access (OFDMA) packet.
 3. The method of claim 1, furthercomprising: entering a power savings mode in accordance with terminatingprocessing of the multi-user packet after processing the PHY header whenthe multi-user packet is not intended for the first wirelesscommunication device; and wherein: the power savings mode involvingpowering down, entering into a stand-by or sleep mode, or powering atleast some circuitry of the first wireless communication device.
 4. Themethod of claim 1, wherein the group definition includes the pluralityof associate identifiers in an order.
 5. The method of claim 4 whereinthe position of the device specific data associated with the firstwireless communication device is determined based on the order of theplurality of associate identifiers in the group definition.
 6. Themethod of claim 1, wherein the device specific data includes a trainingfield.
 7. The method of claim 1, wherein: the PHY header of themulti-user packet is encoded with at least one modulation codingparameter being relatively more robust than at least one additionalmodulation coding parameter by which the remainder of the multi-userpacket is encoded.
 8. The method of claim 7, wherein: the at least onemodulation coding parameter including a first code rate; the at leastone additional modulation coding parameter including a second code rate;and the first code rate being lower than the second code rate.
 9. Themethod of claim 7, wherein: the at least one modulation coding parameterincluding a first modulation; the at least one additional modulationcoding parameter including a second modulation; and the first modulationdifferent from the second modulation.
 10. The method of claim 1,wherein: the PHY header of the multi-user packet encoded with cyclicredundancy check (CRC).
 11. The method of claim 6 wherein the trainingfield is a long training field.
 12. The method of claim 1, wherein: aplurality of wireless stations (STAB) including at least one of thefirst wireless communication device and a third wireless communicationdevice; and the second wireless communication device being an accesspoint (AP).
 13. A method for operating a first wireless communicationdevice, the method comprising: employing at least one antenna forreceiving a group definition from a second wireless communicationdevice, the group definition including a group identifier and aplurality of associate identifiers corresponding to a plurality ofdevices of a group; determining that the first wireless communicationdevice is included in the group based on the group definition bydetermining that an associate identifier corresponding to the firstwireless communication device is included in the plurality of associateidentifiers corresponding to the plurality of devices of the group;determining a position of device specific data associated with the firstwireless communication device, based on the plurality of associateidentifiers included in the group definition; employing the at least oneantenna for receiving a multi-user packet from the second wirelesscommunication device at a time subsequent to receiving the groupdefinition, the multi-user packet including a PHY (physical layer)header, encoded with cyclic redundancy check (CRC), having a groupidentification field (group ID field) that includes the groupidentifier; processing a signal field within the PHY header to determineif the first wireless communication device is included in a plurality ofdevices the multi-user packet is intended for by identifying the groupidentifier in the group ID field; processing the PHY header to extractthe device specific data from the PHY header, based on the position ofthe device specific data, wherein the device specific data includes atraining field; processing a field within the multi-user packetfollowing the PHY header corresponding to the first wirelesscommunication device and as indicated in the PHY header when themulti-user packet is intended for the first wireless communicationdevice; and terminating processing of the multi-user packet afterprocessing the PHY header when the multi-user packet is not intended forthe first wireless communication device, wherein the PHY header of themulti-user packet is encoded with at least one modulation codingparameter being different than at least one additional modulation codingparameter by which the remainder of the multi-user packet is encoded.14. The method of claim 13, wherein: the multi-user packet being amultiple input multiple output (MU-MIMO) packet or an orthogonalfrequency division multiple access (OFDMA) packet.
 15. The method ofclaim 13 wherein the group definition includes the plurality ofassociate identifiers in an order.
 16. The method of claim 15 whereinthe position of the device specific data associated with the firstwireless communication device is determined based on the order of theplurality of associate identifiers in the group definition.
 17. Themethod of claim 13, wherein: the at least one modulation codingparameter including a first code rate; the at least one additionalmodulation coding parameter including a second code rate; and the firstcode rate being relatively lower than the second code rate.
 18. Themethod of claim 13, wherein: the at least one modulation codingparameter including a first modulation; the at least one additionalmodulation coding parameter including a second modulation; and the firstmodulation having a relatively lower order modulation density than thesecond modulation.
 19. The method of claim 13, wherein: a plurality ofwireless stations (STAs) including at least one of the first wirelesscommunication device and a third wireless communication device; and thesecond wireless communication device being an access point (AP).
 20. Anapparatus of a first wireless communication device, comprising: at leastone antenna for receiving a group definition from a second wirelesscommunication device, the group definition including a group identifierand a plurality of associate identifiers corresponding to a plurality ofdevices of a group; a baseband processing module for: determining thatthe apparatus is included in the group based on the group definition bydetermining that an associate identifier corresponding to the apparatusis included in the plurality of associate identifiers corresponding tothe plurality of devices of the group; determining a position of devicespecific data associated with the apparatus, based on the plurality ofassociate identifiers included in the group definition, wherein thedevice specific data includes a training field; wherein the at least oneantenna receives a multi-user packet from the second wirelesscommunication device at a time subsequent to receiving the groupdefinition, the multi-user packet including a PHY (physical layer)header having a group identification field (group ID) indicating aplurality of devices the multi-user packet is intended for; and whereinthe baseband processing module further operates by: processing the PHYheader to determine if the apparatus is included in a plurality ofdevices the multi-user packet is intended for by identifying the groupidentifier in the group ID field; processing the PHY header to extractthe device specific data from the PHY header, based on the position ofthe device specific data; processing a field within the multi-userpacket following the PHY header corresponding to the apparatus and asindicated in the PHY header when the multi-user packet is intended forthe apparatus; terminating processing of the multi-user packet afterprocessing the PHY header when the multi-user packet is not intended forthe apparatus.
 21. The apparatus of claim 20, wherein: the multi-userpacket being a multi-user multiple input multiple output (MU-MIMO)packet or an orthogonal frequency division multiple access (OFDMA)packet.
 22. The apparatus of claim 20, wherein: in accordance with thebaseband processing module terminating processing of the multi-userpacket after processing the PHY header when the multi-user packet is notintended for the apparatus, the apparatus entering a power savings mode;and wherein: the power savings mode involving powering down, enteringinto a stand-by or sleep mode, or powering at least some circuitry ofthe apparatus.
 23. The apparatus of claim 20, wherein the groupdefinition includes the plurality of associate identifiers in an order.24. The apparatus of claim 23 wherein the position of the devicespecific data associated with the first wireless communication device isdetermined based on the order of the plurality of associate identifiersin the group definition.
 25. The apparatus of claim 20, wherein: the PHYheader of the multi-user packet is encoded with at least one modulationcoding parameter being relatively more robust than at least oneadditional modulation coding parameter by which the remainder of themulti-user packet is encoded.
 26. The apparatus of claim 25, wherein:the at least one modulation coding parameter including a first coderate; the at least one additional modulation coding parameter includinga second code rate; and the first code rate being relatively lower thesecond code rate.
 27. The apparatus of claim 25, wherein: the at leastone modulation coding parameter including a first modulation; the atleast one additional modulation coding parameter including a secondmodulation; and the first modulation having a relatively lower ordermodulation density than the second modulation.
 28. The apparatus ofclaim 20, wherein: the PHY header of the multi-user packet encoded withcyclic redundancy check (CRC).